This document discusses protein structure and analysis. It defines proteins as biomolecules composed of amino acid chains that differ from other molecules by containing nitrogen. There are four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure refers to the amino acid sequence. Secondary structures include alpha helices and beta sheets formed by hydrogen bonds between amino acids. Tertiary structure describes the three-dimensional folding of the polypeptide. Quaternary structure is the arrangement of multiple protein subunits. Protein domains and interactions like disulfide bridges stabilize tertiary structures.

1. PROTEIN STRUCTURAL
ANALYSIS:
Presented by:Khansa Asad
Roll no :80020

2. PROTEIN:
 Proteins are large biomolecules, or
macromolecules, consisting of one or more long
chains of amino acid residues. Differs from
carbohydrates and fats because of the
presence of nitrogen.
 The body has at least 30,000 types of
protein, each with a different job.
 The building blocks of all protein
molecules are amino acids

3. PROTEIN:
 There are 20 different amino acids that create different
combinations for specific functions in the body.
 DNA provides the instructions for how the amino acids
will be linked to form the proteins in your body.

4. LEVEL OF PROTEIN
STRUCTURE:
1-primary structure 2-secondary structure
3-Tertiary structure 4-Quaternary structure

5. PRIMARY STRUCTURE OF
PROTEIN:
 Refers to amino acid sequences of the
polypeptide chain.
 Held together by covalent bond.
 Each component of amino acid in a
polypeptide is called a “Residue”.
 Start from N-terminal and end to C-terminal

6. Secondary structure of protein:
 Refers to high regular local sub-structures.
 Defined by pattern of hydrogen bond
between the main chain peptide groups.
 Localized arrangement of adjacent amino
acid formed as the polypeptide chain folds.

7. Alpha Helix And Beeta Sheet:
Alpha helix:
 H-Bond from within a
strand.
 Smaller in size.
 3.6 residues per turn.
 Road like structure.
 Helical coiled.
Beeta sheets:
 H-Bond from between two
or more strand.
 Larger in size.
 More than 3.6 residues per
turn.
 Sheet like structure.
 Fully extended.

8. Super secondary structure(Motif)
 Certain groupings of secondary structural
elements are called MOTIF.

9. TERTIARY STRUCTURE:
 Three Dimensional conformation of a
polypeptide.
 The function of protein depends on its
tertiary structure . If this is disrupted,
 It loses its activity.

10. DOMAINS:
 Polypeptide chains containing more than
200 residues usually fold into two or more
globular clusters known as Domains.
 Interaction
Stabilizing:
 Bonding interaction
Between the side chain of amino acid.
• Hydrogen Bond.
• Ionic bond.
• Disulphide bridges.

11. QUATERNARY STRUCTURE:
 Arrangement of polypeptide sub unit is
called Quaternary structure.
 sub-units are held together by
covalent interaction.
 Water soluble.
 Compact in shape and spherical.

12. LEVEL OF ORGANZITION:

13. PDB(Protein Data
Bank)Homepage:

15. PDB Structure summary:

16. Structural analysis of protein by
PDB: