Components of protein biosynthesis


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this presentation briefly covers the components involved in protein synthesis along with differences between prokeryotic and eukeryotic components.

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Components of protein biosynthesis

  1. 1. Components of protein biosynthesis<br />Nazishjavaid<br />66-BH-BOT-07<br />
  2. 2. INTRODUCTION<br />Protein synthesis is the process in which cells build proteins. <br />The term is sometimes used to refer only to protein translation, but more often to a multistep process; amino acid biosynthesis and transcription.<br />Protein biosynthesis, although very similar, is different for prokaryotes and eukaryotes.<br />
  3. 3. Components of protein biosynthesis<br />Amino Acids<br />Amino Acyl-tRNASynthetase<br />tRNA<br />Ribosomal Subunits<br />mRNA<br />N-formylmethionyl-tRNA<br />Initiation Codon In mRNA (AUG)<br />Initiation Factors<br />ATP<br />GTP<br />AminoacyltRNA<br />Elongation Factors<br />Termination Codon<br />Release Factors<br />Mg2+<br />
  4. 4. Amino acids<br />Amine Group + Carboxyl Group + Side Chain<br />Key elements are Carbon, Hydrogen, Nitrogen And Oxygen<br />Activation of Amino Acids:<br />Carboxyl group must be activated<br />A link must be established between each amino acid and the information in mRNA.<br />
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  6. 6. Transfer RNA<br />Composed of 73-93 nucleotides in length<br />Three letter genetic code and twenty letter code for amino acids.<br />Covalently attached to amino acid<br />Each type of transfer RNA can be attached to only one type of amino acids<br />Strucure of tRNA<br />
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  8. 8. Messenger RNA<br />Molecule of RNA including a chemical “blue print” for a protein product.<br />mRNA is transcribed from a DNA template and carries information to the site of protein synthesis, the ribosome.<br />Genetic information is encoded in codons consisting of three bases each.<br />Each codon encodes for a specific amino acid except the stop codonthat terminates the protein synthesis.<br />
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  10. 10. Ribosome<br />The ribosomes provides the structural site where the mRNA sits.<br />Each tRNA has a nucleotide triplet which bonds to the complementary sequence o the mRNA<br />Ribosomes are tiny organelles that functions to synthesize or build proteins, they connect one amino acid to another forming long strings of proteins known as peptide chain<br />Ribosomes are not one solid piece; they are made of two pieces or subunits.<br />To make the protein, the two subunits of ribosome join together and combine with mRNA.<br />The completed ribosome locks onto the mRNA and begins the process of protein biosynthesis.<br />
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  12. 12. ATP<br />Adenosine-5-triphosphate is a multifunctional nucleotide used in cells as a coenzyme.<br />ATP transports chemical energy within cells for metabolism.<br />Energy for binding the amino acids to tRNA comes from the conversion of ATP to AMP.<br />Mg2+<br />Verstile mineral having major implications<br />Involved in 300 enzymatic reactions like glycolysis etc.<br />Provides stability to ATP by forming magnesium:ATP complex.<br />
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  14. 14. Mg2+play an important role in protein biosynthesis.<br />It is necessary for the activation of amino acid and for the attachment of mRNA to ribosome.<br />Protein synthesis depend on the optimal concentration of Mg2+.<br />Initiation Factor<br />Theseare the proteins that bind to the small subunit of ribosome during the initiation of translation<br />GTP<br />Source of energy for protein synthesis.<br />Used as energy source for <br />binding the tRNA to A site of ribosome.<br />Translocation of ribosme toward the mRNA<br />
  15. 15. Elongation factors<br /><ul><li>Set of proteins that facilitates the events of translational elongation; the steps in protein synthesis from the formation of 1st peptide bond to the last.</li></ul>Stop codon<br /><ul><li>Stop codon or termination codon is a nucleotide triplet within mRNA that signals a termination of translation
  16. 16. UAG; UAA; UGA.</li></ul>Release factors<br /><ul><li>A protein that allows the termination by recognizing the termination codon in a mRNA sequence.</li></li></ul><li>Difference between prokeryotic and eukeryotic protein biosynthesis<br />Prokeryotes<br />Eukeryotes<br />Ribosome is 70s (30s and 40s subunits).<br />Only a single functional site for the initiation of protein synthesis.<br />Starting amino acid is N-formylmethionine.<br />Initiation factors are IF1,IF2 and IF3.<br />Elongation factors: EF-Tu, EF-Ts and EF-G.<br />Release factors:RF-1 RF-2 and RF-3.<br />Ribosome is 80s (40s and 60s).<br />These are polycistronic and contain several initiation and termination sites.<br />Starting amino acid is methionine.<br />Main Initiation factor is IF1 and many more factors involved.<br />Elongation factors: EF-1 and EF-2.<br />Release factors: RF recognizes the termination site<br />