Protein structures determine their functions. There are four levels of protein structure:
1) Primary structure is the amino acid sequence
2) Secondary structure involves local patterns like alpha helices and beta sheets
3) Tertiary structure describes the overall 3D shape formed by secondary structures
4) Quaternary structure refers to the arrangement of multiple polypeptide chains
The most common secondary structures are alpha helices, stabilized by hydrogen bonds between amino acids i and i+4, and beta sheets formed by hydrogen bonding between strands. Protein structure enables functions like catalysis, transport, and information transfer.
The document discusses protein folding, which is the process by which proteins achieve their functional three-dimensional structure from their linear amino acid sequence. It describes the different levels of protein structure, including primary, secondary, tertiary, and quaternary structure. The folding process depends on factors like temperature, pH, and molecular chaperones, which assist in protein folding. Proper folding is required for proteins to carry out their functions in the cell.
The document discusses the levels of protein structure from primary to quaternary structure. It defines the primary structure as the amino acid sequence. Secondary structure forms from hydrogen bonding between amino acids and includes alpha helices and beta pleated sheets. Tertiary structure results from folding influenced by interactions between amino acid side chains. Quaternary structure occurs when multiple polypeptide chains interact to form a protein complex. Examples including hemoglobin and glyceraldehyde-3-phosphate dehydrogenase are provided to illustrate the different levels of structure.
Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. The primary structure is the amino acid sequence. Secondary structures include alpha helices and beta sheets formed by hydrogen bonding of the polypeptide chain. Tertiary structure refers to the overall three-dimensional shape that results from interactions between amino acid side chains. Quaternary structure involves interactions between multiple protein subunits.
Amino acids are the building blocks of proteins. There are 20 standard amino acids that make up proteins. Amino acids have a general structure that includes an amino group, a carboxyl group, and a side chain. They can be classified based on their structure, side chain properties, nutritional requirements, and metabolic fate. Common properties of amino acids include being crystalline solids, existing as zwitterions with an isoelectric point, and having chirality with L and D isomers. Amino acids undergo various reactions due to their amino, carboxyl, and side chain groups.
This document discusses protein structure and folding. It describes the four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure is the amino acid sequence. Secondary structure involves folding into alpha helices or beta sheets. Tertiary structure is the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure refers to interactions between multiple polypeptide chains in a protein. The document also discusses protein folding, denaturation, and misfolding, noting that many neurodegenerative diseases are associated with misfolded protein aggregates.
The document discusses protein folding and the Ramachandran plot. It describes how proteins fold into unique 3D structures determined by their amino acid sequence. This folding occurs very quickly, within milliseconds. The Ramachandran plot, developed by G.N. Ramachandran, maps allowed phi and psi torsion angles for protein backbone conformation. It has been fundamental to understanding protein structure. The document also outlines protein structure levels from primary to quaternary, common secondary structures like alpha helices and beta sheets, and models of the protein folding process.
Biosynthesis of amino acid (essential and non essential)anamsharif
Amino acids are organic compounds that are the building blocks of proteins. There are two types - essential amino acids that must be obtained through diet as the body cannot synthesize them, and non-essential amino acids that the body can synthesize from other compounds if not obtained in diet. The document discusses the biosynthesis pathways of both essential and non-essential amino acids from common metabolic precursors like pyruvate, oxaloacetate, and glutamate. Key enzymes involved in amino acid synthesis include glutamate dehydrogenase, glutamine synthetase, aspartate transaminase, and others.
This document summarizes the biosynthesis of various amino acids from different metabolic precursors. It discusses 6 main families of amino acid biosynthesis defined by their precursor: (1) α-ketoglutarate family including glutamate, glutamine, proline, and arginine; (2) 3-phosphoglycerate family including serine, glycine, and cysteine; (3) oxaloacetate family including aspartate, asparagine, methionine, threonine, and lysine; (4) pyruvate family including alanine, valine, leucine, and isoleucine; (5) phosphoenolpyruvate and erythrose 4-phosphate
The document discusses protein folding, which is the process by which proteins achieve their functional three-dimensional structure from their linear amino acid sequence. It describes the different levels of protein structure, including primary, secondary, tertiary, and quaternary structure. The folding process depends on factors like temperature, pH, and molecular chaperones, which assist in protein folding. Proper folding is required for proteins to carry out their functions in the cell.
The document discusses the levels of protein structure from primary to quaternary structure. It defines the primary structure as the amino acid sequence. Secondary structure forms from hydrogen bonding between amino acids and includes alpha helices and beta pleated sheets. Tertiary structure results from folding influenced by interactions between amino acid side chains. Quaternary structure occurs when multiple polypeptide chains interact to form a protein complex. Examples including hemoglobin and glyceraldehyde-3-phosphate dehydrogenase are provided to illustrate the different levels of structure.
Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. The primary structure is the amino acid sequence. Secondary structures include alpha helices and beta sheets formed by hydrogen bonding of the polypeptide chain. Tertiary structure refers to the overall three-dimensional shape that results from interactions between amino acid side chains. Quaternary structure involves interactions between multiple protein subunits.
Amino acids are the building blocks of proteins. There are 20 standard amino acids that make up proteins. Amino acids have a general structure that includes an amino group, a carboxyl group, and a side chain. They can be classified based on their structure, side chain properties, nutritional requirements, and metabolic fate. Common properties of amino acids include being crystalline solids, existing as zwitterions with an isoelectric point, and having chirality with L and D isomers. Amino acids undergo various reactions due to their amino, carboxyl, and side chain groups.
This document discusses protein structure and folding. It describes the four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure is the amino acid sequence. Secondary structure involves folding into alpha helices or beta sheets. Tertiary structure is the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure refers to interactions between multiple polypeptide chains in a protein. The document also discusses protein folding, denaturation, and misfolding, noting that many neurodegenerative diseases are associated with misfolded protein aggregates.
The document discusses protein folding and the Ramachandran plot. It describes how proteins fold into unique 3D structures determined by their amino acid sequence. This folding occurs very quickly, within milliseconds. The Ramachandran plot, developed by G.N. Ramachandran, maps allowed phi and psi torsion angles for protein backbone conformation. It has been fundamental to understanding protein structure. The document also outlines protein structure levels from primary to quaternary, common secondary structures like alpha helices and beta sheets, and models of the protein folding process.
Biosynthesis of amino acid (essential and non essential)anamsharif
Amino acids are organic compounds that are the building blocks of proteins. There are two types - essential amino acids that must be obtained through diet as the body cannot synthesize them, and non-essential amino acids that the body can synthesize from other compounds if not obtained in diet. The document discusses the biosynthesis pathways of both essential and non-essential amino acids from common metabolic precursors like pyruvate, oxaloacetate, and glutamate. Key enzymes involved in amino acid synthesis include glutamate dehydrogenase, glutamine synthetase, aspartate transaminase, and others.
This document summarizes the biosynthesis of various amino acids from different metabolic precursors. It discusses 6 main families of amino acid biosynthesis defined by their precursor: (1) α-ketoglutarate family including glutamate, glutamine, proline, and arginine; (2) 3-phosphoglycerate family including serine, glycine, and cysteine; (3) oxaloacetate family including aspartate, asparagine, methionine, threonine, and lysine; (4) pyruvate family including alanine, valine, leucine, and isoleucine; (5) phosphoenolpyruvate and erythrose 4-phosphate
This document discusses the different levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure refers to the amino acid sequence. Secondary structure involves local folding into alpha helices or beta sheets. Tertiary structure describes the overall 3D shape of a single polypeptide chain. Quaternary structure refers to the arrangement of multiple polypeptide subunits in a multimeric protein. Recent discoveries are mentioned about determining the structures of specific proteins and learning more about their functions.
Transcription is the process in which a gene's DNA sequence is copied (transcribed) to make an RNA molecule.
RNA polymerase is the main transcription enzyme.
Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins).
RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule.
Transcription ends in a process called termination. Termination depends on sequences in the RNA, which signal that the transcript is finished.
Tertiary Structure basically of Hydrophobic interactions, (interactions in side chains), hydrogen bonding, salt bridges, Vander Waals interactions.
e.g. Globular proteins & Fibrous Proteins
The document discusses the hierarchical structure of proteins from primary to quaternary levels. It describes the primary structure as the amino acid sequence and how this determines the higher order structures. It then explains different structural aspects like secondary structures (helices, sheets), tertiary structure involving folding, and quaternary structure involving multiple subunits. Examples like hemoglobin and domains in large proteins are provided to illustrate these concepts.
Structure of protiens and the applied aspectsMohit Adhikary
The slides explain the structures of proteins, the bond stabilizing the structure of amino acids, the different types of protein structures, the applied aspects and the newer advances in the protein structure.
This document discusses the ionization and pH of amino acids. It begins by providing background on amino acids, noting they contain both amine and carboxylic acid functional groups. It then discusses how amino acids can be classified, including by their side chains. Neutral, acidic, and basic side chains are described. PKa values and isoelectric points are also discussed. The document provides examples of glycine ionization and discusses zwitterion formation in amino acids. Tables of amino acid properties including pKa values and molecular weights are also included.
Proteins have three main functions: catalysis, transport, and information transfer. They are made of amino acids that polymerize and fold into complex three-dimensional structures, from primary to quaternary levels, that determine their unique functions. Protein structure and function are closely linked, as the structure allows proteins to bind specifically to other molecules and carry out reactions.
Multifunctional enzymes contain two or more distinct catalytic activities located in a single polypeptide chain. Fatty acid synthase is a multifunctional enzyme that synthesizes fatty acids through seven distinct enzymatic activities located on three functional domains. DNA polymerase is another multifunctional enzyme that synthesizes DNA and proofreads for errors through its polymerase and exonuclease activities.
This document summarizes the process of protein synthesis through translation. It involves two major steps:
1) Transcription - where the DNA code is transferred to mRNA in the nucleus.
2) Translation - which occurs in the cytoplasm, where the mRNA code is used to assemble amino acids into a protein chain on ribosomes. Transfer RNA molecules carry amino acids and bind to mRNA codons. Elongation and termination steps link the amino acids together and release the finished protein.
Protein structure Lecture for M Sc biology students Anuj Kumar
Presentation on Protein Structure for MSc class by Dr Anuj Kumar Scientist at National Institute of Virology, Indian Council of Medical Research (ICMR)
Also useful for Students preparing of CSIR/JRF NET and LS
This presentation deals with DNA replication in mamalian mitochondria. Mammalian mtDNA is replicated by proteins distinct from those used for nuclear DNA replication. According to the strand displacement model, replication is initiated from two distinct origins, OH and OL.
The document discusses various topics related to protein structure and function. It defines different types of bonds in proteins including peptide bonds, disulfide bonds, and hydrogen bonds. It describes the 20 common amino acids that make up proteins and different secondary structures such as alpha helices and beta sheets. It discusses the four levels of protein structure - primary, secondary, tertiary, and quaternary structure. It also covers protein folding driven by hydrophobic interactions and hydrogen bonding, as well as denaturation of proteins.
The document discusses various aspects of peptide structure and function including:
1. The common secondary structural motifs of peptides including alpha helices, beta sheets, beta turns, and random coils.
2. Techniques used to study peptide conformation such as crystallography, NMR, and CD spectroscopy.
3. Factors that influence peptide structure including amino acid sequence, solvent environment, and intermolecular interactions.
Gives in detail primary, secondary, tertiary and Quaternary structure of proteins. Gives classification of secondary structure: alpha helix, beta pleated sheet and different types of tight turns and explains most commonly found tight turn in proteins i.e. beta turn. Briefs about the Ramachandran plot of proteins, dihedral or torsion angles and explains why glycine and proline act as alpha helix breakers. Explains tertiary structure of proteins and different covalent and non covalent bonds in the tertiary structure and relative importance of these bonding interactions. Details about the quaternary structure of proteins and explains why hemoglobin is a quaternary protein and insulin is not.
The key forces stabilizing nucleic acid structure are hydrogen bonding, base stacking, hydrophobic interactions, and ionic bonding. Hydrogen bonding occurs between complementary nucleotide bases on opposite strands. Base stacking involves hydrophobic interactions between stacked aromatic nucleotide bases within each strand. Hydrophobic interactions bury hydrophobic bases in the core of the double helix, increasing stability. Ionic interactions between phosphate groups and counterions in solution also stabilize the structure.
Proteins have a variety of functions in cells including enzymes, structural components, transporters, motors, and signaling molecules. A protein's unique 3D shape, determined by its amino acid sequence, allows it to carry out its specific function. The polypeptide backbone forms secondary structures like alpha helices and beta sheets. Non-covalent interactions further guide protein folding into a stable tertiary structure. Quaternary structure involves interactions between multiple polypeptide chains. Post-translational modifications and ligand binding regulate protein activity.
The document discusses the Hill equation, which was formulated by Archibald Hill in 1910 to describe the sigmoidal oxygen binding curve of hemoglobin. The Hill equation can be used to describe the fraction of a macromolecule saturated by a ligand as a function of the ligand's concentration. It is useful for determining the degree of cooperativity between ligand binding sites. A Hill coefficient of n > 1 indicates positively cooperative binding, n < 1 indicates negatively cooperative binding, and n = 1 indicates noncooperative binding.
N-terminal tails of histones are the most accessible regions for modifications. These post-translational modification (PTM) of histones is a crucial step in epigenetic regulation of a gene.
The document provides information on protein structure and function including:
- Proteins have a variety of functions including catalysis, structure, transport, signaling, and storage.
- The central dogma of molecular biology describes how DNA is transcribed into mRNA and then translated into proteins.
- Protein structure is determined by each protein's unique amino acid sequence and how they fold into secondary structures like alpha helices and beta sheets.
- The alpha helix and beta sheet are the most common secondary structures, stabilized by hydrogen bonds between amino acids in the backbone.
- Proteins are composed of amino acid polymers called polypeptides linked by peptide bonds. They form complex 3D structures through folding at various levels - primary, secondary, tertiary, and quaternary.
- Secondary structure includes alpha helices, beta sheets, and beta turns formed by hydrogen bonding between amino acids in the polypeptide chain.
- Tertiary structure is the overall 3D shape of a protein formed by interactions between amino acid side chains. Quaternary structure involves the assembly of multiple protein subunits.
- Myoglobin and hemoglobin are oxygen-binding proteins with heme prosthetic groups. Hemoglobin has a cooperative binding mechanism that allows for oxygen delivery and release in tissues.
This document discusses the different levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure refers to the amino acid sequence. Secondary structure involves local folding into alpha helices or beta sheets. Tertiary structure describes the overall 3D shape of a single polypeptide chain. Quaternary structure refers to the arrangement of multiple polypeptide subunits in a multimeric protein. Recent discoveries are mentioned about determining the structures of specific proteins and learning more about their functions.
Transcription is the process in which a gene's DNA sequence is copied (transcribed) to make an RNA molecule.
RNA polymerase is the main transcription enzyme.
Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins).
RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule.
Transcription ends in a process called termination. Termination depends on sequences in the RNA, which signal that the transcript is finished.
Tertiary Structure basically of Hydrophobic interactions, (interactions in side chains), hydrogen bonding, salt bridges, Vander Waals interactions.
e.g. Globular proteins & Fibrous Proteins
The document discusses the hierarchical structure of proteins from primary to quaternary levels. It describes the primary structure as the amino acid sequence and how this determines the higher order structures. It then explains different structural aspects like secondary structures (helices, sheets), tertiary structure involving folding, and quaternary structure involving multiple subunits. Examples like hemoglobin and domains in large proteins are provided to illustrate these concepts.
Structure of protiens and the applied aspectsMohit Adhikary
The slides explain the structures of proteins, the bond stabilizing the structure of amino acids, the different types of protein structures, the applied aspects and the newer advances in the protein structure.
This document discusses the ionization and pH of amino acids. It begins by providing background on amino acids, noting they contain both amine and carboxylic acid functional groups. It then discusses how amino acids can be classified, including by their side chains. Neutral, acidic, and basic side chains are described. PKa values and isoelectric points are also discussed. The document provides examples of glycine ionization and discusses zwitterion formation in amino acids. Tables of amino acid properties including pKa values and molecular weights are also included.
Proteins have three main functions: catalysis, transport, and information transfer. They are made of amino acids that polymerize and fold into complex three-dimensional structures, from primary to quaternary levels, that determine their unique functions. Protein structure and function are closely linked, as the structure allows proteins to bind specifically to other molecules and carry out reactions.
Multifunctional enzymes contain two or more distinct catalytic activities located in a single polypeptide chain. Fatty acid synthase is a multifunctional enzyme that synthesizes fatty acids through seven distinct enzymatic activities located on three functional domains. DNA polymerase is another multifunctional enzyme that synthesizes DNA and proofreads for errors through its polymerase and exonuclease activities.
This document summarizes the process of protein synthesis through translation. It involves two major steps:
1) Transcription - where the DNA code is transferred to mRNA in the nucleus.
2) Translation - which occurs in the cytoplasm, where the mRNA code is used to assemble amino acids into a protein chain on ribosomes. Transfer RNA molecules carry amino acids and bind to mRNA codons. Elongation and termination steps link the amino acids together and release the finished protein.
Protein structure Lecture for M Sc biology students Anuj Kumar
Presentation on Protein Structure for MSc class by Dr Anuj Kumar Scientist at National Institute of Virology, Indian Council of Medical Research (ICMR)
Also useful for Students preparing of CSIR/JRF NET and LS
This presentation deals with DNA replication in mamalian mitochondria. Mammalian mtDNA is replicated by proteins distinct from those used for nuclear DNA replication. According to the strand displacement model, replication is initiated from two distinct origins, OH and OL.
The document discusses various topics related to protein structure and function. It defines different types of bonds in proteins including peptide bonds, disulfide bonds, and hydrogen bonds. It describes the 20 common amino acids that make up proteins and different secondary structures such as alpha helices and beta sheets. It discusses the four levels of protein structure - primary, secondary, tertiary, and quaternary structure. It also covers protein folding driven by hydrophobic interactions and hydrogen bonding, as well as denaturation of proteins.
The document discusses various aspects of peptide structure and function including:
1. The common secondary structural motifs of peptides including alpha helices, beta sheets, beta turns, and random coils.
2. Techniques used to study peptide conformation such as crystallography, NMR, and CD spectroscopy.
3. Factors that influence peptide structure including amino acid sequence, solvent environment, and intermolecular interactions.
Gives in detail primary, secondary, tertiary and Quaternary structure of proteins. Gives classification of secondary structure: alpha helix, beta pleated sheet and different types of tight turns and explains most commonly found tight turn in proteins i.e. beta turn. Briefs about the Ramachandran plot of proteins, dihedral or torsion angles and explains why glycine and proline act as alpha helix breakers. Explains tertiary structure of proteins and different covalent and non covalent bonds in the tertiary structure and relative importance of these bonding interactions. Details about the quaternary structure of proteins and explains why hemoglobin is a quaternary protein and insulin is not.
The key forces stabilizing nucleic acid structure are hydrogen bonding, base stacking, hydrophobic interactions, and ionic bonding. Hydrogen bonding occurs between complementary nucleotide bases on opposite strands. Base stacking involves hydrophobic interactions between stacked aromatic nucleotide bases within each strand. Hydrophobic interactions bury hydrophobic bases in the core of the double helix, increasing stability. Ionic interactions between phosphate groups and counterions in solution also stabilize the structure.
Proteins have a variety of functions in cells including enzymes, structural components, transporters, motors, and signaling molecules. A protein's unique 3D shape, determined by its amino acid sequence, allows it to carry out its specific function. The polypeptide backbone forms secondary structures like alpha helices and beta sheets. Non-covalent interactions further guide protein folding into a stable tertiary structure. Quaternary structure involves interactions between multiple polypeptide chains. Post-translational modifications and ligand binding regulate protein activity.
The document discusses the Hill equation, which was formulated by Archibald Hill in 1910 to describe the sigmoidal oxygen binding curve of hemoglobin. The Hill equation can be used to describe the fraction of a macromolecule saturated by a ligand as a function of the ligand's concentration. It is useful for determining the degree of cooperativity between ligand binding sites. A Hill coefficient of n > 1 indicates positively cooperative binding, n < 1 indicates negatively cooperative binding, and n = 1 indicates noncooperative binding.
N-terminal tails of histones are the most accessible regions for modifications. These post-translational modification (PTM) of histones is a crucial step in epigenetic regulation of a gene.
The document provides information on protein structure and function including:
- Proteins have a variety of functions including catalysis, structure, transport, signaling, and storage.
- The central dogma of molecular biology describes how DNA is transcribed into mRNA and then translated into proteins.
- Protein structure is determined by each protein's unique amino acid sequence and how they fold into secondary structures like alpha helices and beta sheets.
- The alpha helix and beta sheet are the most common secondary structures, stabilized by hydrogen bonds between amino acids in the backbone.
- Proteins are composed of amino acid polymers called polypeptides linked by peptide bonds. They form complex 3D structures through folding at various levels - primary, secondary, tertiary, and quaternary.
- Secondary structure includes alpha helices, beta sheets, and beta turns formed by hydrogen bonding between amino acids in the polypeptide chain.
- Tertiary structure is the overall 3D shape of a protein formed by interactions between amino acid side chains. Quaternary structure involves the assembly of multiple protein subunits.
- Myoglobin and hemoglobin are oxygen-binding proteins with heme prosthetic groups. Hemoglobin has a cooperative binding mechanism that allows for oxygen delivery and release in tissues.
Amino acids and structure of protein.pptxDrSaraniSen
This presentation will provide you from the basic to the details idea of protein structure. How amino acids are interact to form a 3D- structure of protein. I will give a complete details about amino acid to protein formation and the basic properties of proteins
Amino acids are the building blocks of proteins. They contain carbon, hydrogen, oxygen, nitrogen and a distinctive side chain. There are 20 common amino acids that serve as monomers for protein synthesis. Amino acids differ in their side chains, which influence solubility. The general structure includes an amino group, carboxyl group, hydrogen and R group. Amino acids form proteins through peptide bonds between their amino and carboxyl groups. Proteins have primary, secondary, tertiary and quaternary levels of structure determined by amino acid sequence and bonding.
This document discusses principles of protein structure, including primary, secondary, and supersecondary structure. It covers the following key points:
- Primary structure refers to the amino acid sequence of a protein. There are 20 common amino acids that make up protein sequences.
- Secondary structure includes common elements like alpha helices and beta sheets. Alpha helices are right-handed coils stabilized by hydrogen bonds between amino acids four positions apart in the sequence. Beta sheets consist of beta strands connected laterally or anti-parallel by hydrogen bonds.
- Supersecondary structure refers to recurrent structural motifs formed by combinations of secondary structure elements, like beta-alpha-beta motifs or helix-loop-helix motifs. Larger domains
The document describes the four levels of protein structure:
1) Primary structure is the linear sequence of amino acids joined by peptide bonds.
2) Secondary structure involves localized patterns like alpha helices and beta sheets formed by hydrogen bonds.
3) Tertiary structure is the overall 3D shape of the polypeptide chain formed by interactions like disulfide bridges, hydrogen bonds, and hydrophobic interactions.
4) Quaternary structure refers to complexes of multiple polypeptide subunits.
Here are the key points about the effects on hemoglobin's O2 affinity:
a) Drop in pH of blood plasma - O2 affinity decreases, as H+ competes with O2 binding sites
b) Decrease in partial pressure of CO2 in lungs - O2 affinity increases, as less CO2 means less competition
c) Increase in BPG levels - O2 affinity decreases, as BPG binds allosterically and induces a shape change
d) Increase in CO - O2 affinity decreases greatly, as CO has a much higher affinity for heme than O2
Dystrophin is a high molecular weight cytoskeletal protein that localizes to the cytoplasmic face of the sarcolemma. It has four domains - an actin binding domain, a central rod domain composed of spectrin-like repeats, a cysteine-rich domain, and a carboxy-terminal domain. Dystrophin forms the dystrophin-glycoprotein complex with other proteins like dystroglycans and sarcoglycans to connect the actin cytoskeleton to the extracellular matrix. Mutations in dystrophin cause Duchenne/Becker muscular dystrophy by disrupting this connection and leading to muscle degeneration.
This document discusses the structure of proteins at different levels, including primary, secondary, tertiary and quaternary structure. It explains that primary structure is the amino acid sequence, and secondary structure includes alpha helices and beta sheets formed by hydrogen bonding. Tertiary structure involves the folding of secondary structure elements into the final three-dimensional shape. The document outlines methods for determining primary structure and describes concepts like the Ramachandran plot that show allowed phi and psi angles. It provides examples of common motifs in tertiary structure and defines domains.
Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. The primary structure is the linear sequence of amino acids. Regular patterns of hydrogen bonding in the primary structure give rise to secondary structures like alpha helices and beta sheets. The overall three-dimensional folded structure of a protein is its tertiary structure, stabilized by interactions between R groups. Quaternary structure involves the assembly of multiple protein subunits. Common protein structures were discussed including fibrous proteins, globular proteins, and structural elements like helices and sheets.
This document provides an overview of protein structure and function. It discusses the central dogma of life, the 20 common amino acids that make up proteins, and how they fold into defined structures like alpha helices and beta sheets. Key concepts covered include the hydrophobic effect that drives protein folding, domains as fundamental units of structure, and the three main classes of protein structures - alpha, beta, and alpha/beta domains. Real-world protein examples are also briefly mentioned.
B.Sc. Biochem II Biomolecule I U 3.1 Structure of ProteinsRai University
This document discusses the different levels of protein structure:
- Primary structure is the amino acid sequence of the protein chain. Secondary structure describes regular structures like alpha helices and beta sheets formed by hydrogen bonds. Tertiary structure describes the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure describes how multiple protein subunits assemble into larger structures. Examples like collagen, insulin, and hemoglobin are provided to illustrate these levels of structure.
BT631-5-primary_secondary_structures_proteinsRajesh G
This document discusses the different levels of protein structure, including primary, secondary, tertiary, and quaternary structure. It provides details on the primary structure, including that it is defined by the unique sequence of amino acid residues in the polypeptide chain. It also discusses various types of secondary structure like alpha helices, beta strands, and turns, describing their characteristic hydrogen bonding patterns, diameters, and other structural features. Methods for determining protein primary and secondary structure are also summarized.
This document discusses protein structure and synthesis. It begins by defining proteins and peptides, and the 20 amino acids that make up proteins. It then describes the four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure is the linear sequence of amino acids in the polypeptide chain. Secondary structure results from hydrogen bonding within the chain, forming structures like alpha helices. Tertiary structure describes the final 3D shape from chain folding. Quaternary structure involves the interaction of multiple peptide chains in an oligomeric protein. The document also outlines peptide bond formation and different peptide synthesis methods.
This document discusses protein structure and synthesis. It begins by defining proteins and peptides, and the 20 amino acids that make up proteins. It then describes the four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure is the linear sequence of amino acids in the polypeptide chain. Secondary structure results from hydrogen bonding within the chain, forming structures like alpha helices. Tertiary structure describes the final 3D shape from chain folding. Quaternary structure involves the interaction of multiple peptide chains in an oligomeric protein. The document also outlines peptide bond formation and different peptide synthesis methods.
In this pdf amino acid and protein classification is given in excellent manner.
Amino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life.When proteins are digested or broken down, amino acids are left. The human body uses amino acids to make proteins to help the body:Break down food,Grow,Repair body tissue,Perform many other body functions.Amino acids can also be used as a source of energy by the body.
Amino acids are classified into three groups:
Essential amino acids
Nonessential amino acids....
Function and Classification of protein given in this pdf .
Structure of proteins given in this pdf with different types of interaction between amino acids like hydrogen bonding , intermolecular and intramolecular bondings. Also structure of protein given in primary, secondary, tertiary and quarternary forms.
Physicochemical properties of protein also given in this pdf.
The document discusses the structure of proteins at various levels of organization:
- Proteins are composed of amino acids linked together by peptide bonds to form polypeptide chains. The sequence and interactions of these chains determine the protein's structure.
- There are four levels of protein structure - primary, secondary, tertiary, and quaternary. Secondary structure includes alpha helices and beta sheets formed by hydrogen bonding between amino acids in the chain. Tertiary structure describes the overall 3D shape formed by interactions between amino acid side chains. Quaternary structure involves the interaction of multiple polypeptide chains.
- Protein structure enables proteins to perform their diverse functions through processes like enzyme catalysis, oxygen transport, and providing structure
Levels of protein structure include primary, secondary, tertiary, and quaternary. The primary structure is the amino acid sequence. Secondary structure involves hydrogen bonding between amino acids to form alpha helices and beta sheets. Tertiary structure describes how secondary structures fold in 3D space, stabilized by noncovalent bonds. Quaternary structure involves the interaction of multiple polypeptide chains. Protein folding is assisted by chaperone proteins and errors can lead to diseases like Alzheimer's and prion diseases.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
2. 2
Protein Functions
• Comes from Greek Work Proteios – PRIMARY
• Fundamental to virtually all cellular processes
– WHAT DON’T THEY DO!
– Proteins play a key role in biological processes. They can fulfill a vast
variety of tasks.
1. Enzymes/Cellular Signaling
Enzymes catalyze the complex set of chemical reactions that are
collectively referred to as life.
These chemical reactions are regulated by proteins, which act either
directly as components of enzymes or indirectly in the form of chemical
messengers, or their receptors.
3. 2. Antibodies
• The proteins of the immune system, such as the immunoglobulins, form
an essential biological defense system in higher animals.
3. Transport of materials
• Proteins are engaged in the transport and storage of biologically
important substances such as metal ions, oxygen, glucose, lipids, and
many other molecules.
“All of this results from the peculiar structure of proteins”
• Protein function can be understood only in terms of proteins structure. That
means the structure of a protein determines its biochemical function.
4. Protein Functions
• Three examples of protein functions
– Catalysis:
Almost all chemical reactions in a living
cell are catalyzed by protein enzymes.
– Transport:
Some proteins transports various
substances, such as oxygen, ions, and so
on.
– Information transfer:
For example, hormones.
Alcohol
dehydrogenase
oxidizes alcohols
to aldehydes or
ketones
Haemoglobin
carries oxygen
Insulin controls
the amount of
sugar in the
blood
5. Protein structure
• Primary structure is the linear sequence of amino acids in the
polypeptide chain(s) of a protein.
• Secondary structure- the local spatial arrangement of a
polypeptides backbone atoms without regard to the
conformations of its side chains.
Secondary Structure consists of local regions of poly peptide chains
that have a regular conformation (- helices, - sheets etc) which
is stabilized by H-bonds.
6. • Tertiary structure - the overall arrangement of secondary
structure elements.
• Tertiary Structure refers to the 3-D configuration of an entire
polypeptide chain .This includes - helices & - sheets and regions
that are globular or spherical
• Quaternary structure- the arrangement of several polypeptide
chains
• Quaternary Structure consists of number of polypeptide chains or
subunits joined by non covalent interactions.
7.
8. Typical bonds in protein molecules
Covalent bonds
Non-covalent bonds
Peptide bond
Disulfide bond
Hydrogen bond
Ionic bond
Hydrophobic interactions
9. Primary Structure
It’s the sequence of amino acids linked through peptide bonds, Covalent
backbone of the protein.
H2N-Glu-Ala-Val-Ser-Leu-Ala-Lys-Cys-COOH
10. • The particular sequence of amino acids in a peptide or protein is referred to as
the primary structure.
--For example, a hormone that stimulates the thyroid to release thyroxine (TSH)
consists of a tri-peptide Glu-His-Pro.
--Although other sequences are possible for these three amino acids, only the
tri-peptide with the Glu-His-Pro sequence of amino acids has hormonal activity.
-- Thus the biological function of peptides as well as proteins depends on the
order of the amino acids.
11. Amino Acids
• While their name implies that amino acids are compounds that contain an
—NH2 group and a —COOH group, these groups are actually present as —
NH3
+ and —COO– respectively.
• More than 700 amino acids occur naturally, but 20 of them are especially
important.
• These 20 amino acids are the building blocks of proteins. All are -amino
acids.
• They differ in respect to the
group attached to the carbon.
15. 15
Amino acids exist as a zwitterion:
a dipolar ion having both a formal positive and formal negative
charge (overall charge neutral).
Amino acids are amphoteric:
They can react as either an acid or a base. Ammonium ion
acts as an acid, the carboxylate as a base.
Isoelectric point (pI):
The pH at which the amino acid exists largely in a neutral,
zwitterionic form (influenced by the nature of the side chain)
19. Peptide Bond
• Joins amino acids
• Covalent, strong bond
• Not broken by usual denaturing agents like heating or
high salt concentration
• Can be broken by Prolonged exposure to strong acids
or base at elevated temperatures or by enzyme
digestion.
• Rigid and planar
• 40% double bond character
– Caused by resonance
21. – Partial double bond character (distance is 1.33 Å (angstroms)
which is midway in a single bond 1.45 Å and a double bond
1.23Å)
– Double bond disallows rotation around the bond between
Carbonyl carbon and the nitrogen of the peptide bond
– The bonds between the alpha carbon and the alpha amino
groups can be freely rotated.
– But they are limited by the size and character of the R Groups
23. 23
• Backbone can swivel:
DIHEDRAL ANGLES
• 2 per Amino Acid
• Proteins can be 100’s of
Amino Acids in length!
– Lots of freedom of
movement
24.
25. Many of the possible conformations about an α-carbon between
two peptide planes are forbidden because of steric crowding.
Several noteworthy examples are shown here.
27. Backbone Torsion Angles
• ω angle tends to be planar (0º - cis, or 180 º - trans) due to
resonance stabilization
• φ and ψ are flexible, therefore rotation occurs here
• However, φ and ψ of a given amino acid residue are limited due
to steric hindrance
• Only 10% of the area of the {φ, ψ} space is generally observed
for proteins
• First noticed by G.N. Ramachandran
28. G.N. Ramachandran
8 October 1922 – 7 April 2001
• Indian Physicist, Student of CV Raman.
• Used computer models of small polypeptides
to systematically vary φ and ψ with the objective
of finding stable conformations
• For each conformation, the structure was
examined for close contacts between atoms
• Atoms were treated as hard spheres with
dimensions corresponding to their van der Waals
radii
29. Ramachandran Plot
• Plot of φ vs. ψ
• Repeating values of φ and ψ along the chain result in regular
structure
• By Applying the values of φ and ψ in the Ramachandran plot we can
predict the secondary structure of a protein
• For example, repeating values of φ ~ -57° and ψ ~ -47° give a right-
handed helical fold (the alpha-helix)
30. • Therefore, φ and ψ angles which cause spheres to collide correspond to sterically
disallowed conformations of the polypeptide backbone
31.
32. Ramachandran Plot
• White = sterically disallowed conformations (atoms in the
polypeptide come closer than the sum of their van der Waals radii)
• Red = sterically allowed regions (namely right-handed alpha helix
and beta sheet)
• Yellow = sterically allowed if shorter radii are used (i.e. atoms
allowed closer together; brings out left-handed helix)
33. • The structure of cytochrome C-256 shows many segments of helix and the
Ramachandran plot shows a tight grouping of φ, ψ angles near -50,-50
alpha-helix
cytochrome C-256 Ramachandran plot
34. • Linus Pauling and Robert Corey describes the -helix in 1951
• In this structure the polypeptide backbone is tightly wound around an
imaginary axis drawn longitudinally through the middle of the helix in a
right-handed manner.
• R groups of the amino acid residues protrude outward from the helical
backbone.
• It helps to avoid the steric interference with the polypeptide backbone
• The repeating unit is a single turn of the helix, having a pitch of 5.4 Å.
• Each helical turn includes 3.6 amino acid residues.
-HELIX
35. • The helices of proteins have an
average length of 12 residues,
which corresponds to over three
helical turns, and a length of 18 Å.
• Generally, about one-fourth of all
amino acid residues in
polypeptides are found in helices,
the exact fraction varying greatly
from one protein to the next.
36. • Why does the helix form more readily than many other possible conformations?
• The structure is stabilized by a hydrogen bond
• A helix makes optimal use of internal hydrogen bonds.
• Hydrogen bonding is seen between the nth and n+4 the residue
• This results in a strong hydrogen bond has the nearly optimum distance of 2.8 Å
• Within the helix, every peptide bond (except those close to each end of the helix)
participates in such hydrogen bonding.
• Each successive turn of the helix is held to adjacent turns by three to four hydrogen
bonds.
• All the hydrogen bonds combined give the entire helical structure considerable
stability.
37. The α-Helix
Four different representations of the α-helix
First proposed by Linus Pauling and Robert Corey in 1951
A ubiquitous component of proteins, stabilized by H bonds
38. • Residues per turn: 3.6
• Rise per residue: 1.5 Angstroms
• Rise per turn (pitch): 3.6 x 1.5A = 5.4 Angstroms
• The backbone loop that is closed by any H-bond
in an alpha helix contains 13 atoms
• phi = -57 degrees, psi = -47 degrees
• The non-integral number of residues per turn was
a surprise to crystallographers
39. Amino Acid Sequence Affects Helix Stability;
• Not all polypeptides can form a stable helix.
• Interactions between amino acid side chains can stabilize or destabilize this
structure.
• For example, if a polypeptide chain has a long block of Glu residues, this
segment of the chain will not form a helix at pH 7.0.
• The negatively charged carboxyl groups of adjacent Glu residues repel each
other so strongly that they prevent formation of the helix.
• Another constraint on the formation of the helix is the presence of Pro or Gly
residues.
40. • In proline, the nitrogen atom is part of a rigid ring and rotation about the NOC
bond is not possible. Thus, a Pro residue introduces a destabilizing kink in an
helix.
• In addition, the nitrogen atom of a Pro residue in peptide linkage has no
substituent hydrogen to participate in hydrogen bonds with other residues.
• For these reasons, proline is only rarely found within an helix.
• Glycine occurs infrequently in helices for a different reason:
• It has more conformational flexibility than the other amino acid residues.
Polymers of glycine tend to take up coiled structures quite different from an
helix.
41. Five different kinds of constraints affect the stability of a helix:
• (1)The electrostatic repulsion (or attraction) between successive amino
acid residues with charged R groups
• (2) The bulkiness of adjacent R groups,
• (3) The interactions between R groups spaced three (or four) residues
apart,
• (4) The occurrence of Pro and Gly residues, and
• (5) The interaction between amino acid residues at the ends of the helical
segment and the electric dipole inherent to the helix
42. Other (Rarer) Helix Types - 310
• Less favorable geometry
• Pitch is 6.0Å
• Rise per residue is 2.0 Å
• 3 residues per turn with n+3 not n+4
• Hence narrower and more elongated
• Usually seen at the end of an alpha helix
• frequently occurs as a single turn transition between the end
of an a-helix and the next portion of the polypeptide chain
43. Other (Very Rare) Helix Types - Π
• Less favorable geometry
• p helix (4.416 helix): p=5.2Å
• Rise per residue= 1.3 Å
• 4 residues per turn with i+5 not i+4
• Squat and constrained
44. The Beta-Pleated Sheet
• Also first postulated by Pauling and Corey, 1951
• Formed through by side-by-side alignment of polypeptide strands
• Polypeptide chains are held together by hydrogen bonds between the
peptide chains.
• R groups of extend above and below the sheet
• Rise per residue:
– 3.47 Angstroms for antiparallel strands
– 3.25 Angstroms for parallel strands
– Each strand of a beta sheet may be pictured as a helix with two
residues per turn
45. An antiparallel β-pleated sheet. R groups project alternately above and below the plane of the
sheet. Sheet structure is derived from the tetrahedral placement of substituents on the α
carbon atoms. This is the more stable form of a β-sheet.
46. • Comparison of β-sheet with α-helix
• The beta pleated sheet differs markedly from the a helix in that it is a
sheet rather than a rod.
• The polypeptide chain in the beta pleated sheet is almost fully extended
rather than being tightly coiled as in the a helix.
• The axial distance between adjacent amino acids is 3.5 A, in contrast with
1.5 A for the a helix.
• beta pleated sheet is stabilized by hydrogen bonds between NH and CO
groups in different polypeptide strands, whereas in the a helix the
hydrogen bonds are between NH and CO groups in the same polypeptide
chain.
47. • Adjacent strands in a beta pleated sheet can run in the
same direction (parallel beta sheet) or in opposite
directions (antiparallel beta sheet).
• H-bonds perpendicular to long axis
• β-sheets are composed of two or more polypeptide
chains or extended segments of the same polypeptide
48. TYPES OF -PLEATED SHEET
Antiparallel Parallel
Antiparallel is more stable than parallel
Both models are found in proteins
49.
50. β - turns
Beta-turn loops allow for protein
compaction, since the hydrophobic amino
acids tend to be in the interior of the
protein, while the hydrophilic residues
interact with the aqueous environment.
(aka beta bend, tight turn)
Permits the change of direction of the peptide chain
to get a folded structure.
carbonyl C of one residue is H-bonded to the amide
proton of a residue three residues away
proline and glycine are prevalent in beta turns
51. 51
Other Secondary Structures – Loop or Coil
• Often functionally significant
• Different types
– Hairpin loops (aka reverse turns) – often between
anti-parallel beta strands
– Omega loops – beginning and end close (6-16
residues)
– Extended loops – more than 16 residues
52. Complete three-dimensional shape of
a given protein.
Represent the spatial relationship of
the different secondary structures to
one another within a polypeptide
chain and how these secondary
structures themselves fold into the
three-dimensional form of the
protein.
Tertiary structure
The spiral regions represent sections of the
polypeptide chain that have an α-helical
structure, while the broad arrows represent β-
pleated sheet structures.
53. A domain is a basic structural unit within a
protein molecule.
Part of protein that can fold into a stable
structure independently.
Different domains can possess different
functions.
Proteins can have one to many domains
depending on protein size.
A polypeptide with 200 amino acids consists
of two or more domains.
Domains are usually connected with
relatively flexible areas of protein.
Protein domain
Pyruvate kinase (a
monomeric protein):
three domains
Tertiary structure: Describes the relationship of different
domains to one another within a protein.
54. Tertiary structure is based on various types of interactions between
the side-chains of the peptide chain.
56. Globular Proteins
Globular proteins fold up into compact, spherical
shapes.
Their functions are related to cell metabolism:
biosynthesis and biodegradation, transport, catalytic
function.
Hydrophobic R-groups are oriented into inner part of
the protein molecule, while hydrophilic R-groups are
pointed towards molecule edges.
Globular proteins are water soluble.
57. Example: myoglobin
Globular protein that stores
oxygen in muscles
A single peptide chain that
is mostly -helix
O2 binding pocket is formed
by a heme group and specific
amino acid side-chains that
are brought into position by
the tertiary structure
58. Much or most of the polypeptide chain is
parallel to a single axis
Fibrous proteins are often mechanically
strong and highly cross-linked
Fibrous proteins are usually insoluble
Usually play a structural role
Fibrous proteins
59. Fibrous Proteins: Keratins
• For example, -keratins are fibrous proteins that make
hair, fur, nails and skin
- hair is made of twined fibrils
- the -helices are held together by disulfide bonds
60. Fibrous proteins: Fibroin
Fibroin
Fibroins are the silk proteins. They also form the spider webs
Made with a -sheet structures with Gly on one face and
Ala/Ser on the other
Fibroins contain repeats of [Gly-Ala-Gly-Ala-Gly-Ser-Gly-Ala-
Ala-Gly-(Ser-Gly-Ala-Gly-Ala-Gly)8]
The -sheet structures stack on top of each other
Bulky regions with valine and tyrosine interrupt the -sheet
and allow the stretchiness
61. Collagen is formed from tropocollagen subunits. The
triple helix in tropocollagen is highly extended and
strong.
Features:
Three separate polypeptide chains arranged as a
left-handed helix (note that an a-helix is right-
handed).
3.3 residues per turn
Each chain forms hydrogen bonds with the other
two: STRENGTH!
Nearly one residue out of three is Gly
Proline content is unusually high
Many modified amino acids present:
4-hydroxyproline
3-hydroxyproline
5-hydroxylysine
Pro and HydroxyPro together make 30% of amino
acids.
Collagen amino
acid composition:
Fibrous proteins: Collagen is a Triple Helix
62. Covalent cross-links in collagen: alteration of
mechanical properties of collagen
Catalyzed by lysyl amino oxidase
63. 1. Compact protein structure Extended protein structure
2. Soluble in water (or in lipid Insoluble in water (or in lipid
bilayers) bilayers)
3. Secondary structure is а complex Secondary structure is simple
with a mixture of a-helix, b-sheet with predominant one type only
and loop structures
4. Quaternary structure is held Quaternary structure is usually
together by noncovalent forces held together by covalent
bridges
5. Functions in all aspects of Functions in structure of the
body metabolism (enzymes, transport, or cell (tendons, bones, muscle,
immune protection, hormones, etc). ligaments, hair, skin)
Globular proteins vs Fibrous proteins
64. Quaternary structure of proteins
Monomeric proteins:
– built of a single polypeptide chain.
Oligomeric proteins:
– built of more than one polypeptide chains called
subunits or monomers.
65. Quaternary structure describes the joining of two
or more polypeptide subunits.
The subunits each have their own tertiary
structure.
Bonds – non-covalent interactions.
Subunits can either function independently or
work co-operatively.
Dissociation of a subunit results in loss of function.
66. For example: Hemoglobin
A globular protein that consists of four subunits (2α and 2β, of two
different types (α and β)
Each subunit contains a heme group for O2 binding
Binding O2 to one heme facilitates O2 binding by other subunits
Replacement of even one amino acid in primary structure with
another amino acid is critical for the function of the protein.