Components of protein biosynthesis
- 1. Components of protein biosynthesisNazishjavaid66-BH-BOT-07
- 2. INTRODUCTIONProtein synthesis is the process in which cells build proteins. The term is sometimes used to refer only to protein translation, but more often to a multistep process; amino acid biosynthesis and transcription.Protein biosynthesis, although very similar, is different for prokaryotes and eukaryotes.
- 3. Components of protein biosynthesisAmino AcidsAmino Acyl-tRNASynthetasetRNARibosomal SubunitsmRNAN-formylmethionyl-tRNAInitiation Codon In mRNA (AUG)Initiation FactorsATPGTPAminoacyltRNAElongation FactorsTermination CodonRelease FactorsMg2+
- 4. Amino acidsAmine Group + Carboxyl Group + Side ChainKey elements are Carbon, Hydrogen, Nitrogen And OxygenActivation of Amino Acids:Carboxyl group must be activatedA link must be established between each amino acid and the information in mRNA.
- 6. Transfer RNAComposed of 73-93 nucleotides in lengthThree letter genetic code and twenty letter code for amino acids.Covalently attached to amino acidEach type of transfer RNA can be attached to only one type of amino acidsStrucure of tRNA
- 8. Messenger RNAMolecule of RNA including a chemical “blue print” for a protein product.mRNA is transcribed from a DNA template and carries information to the site of protein synthesis, the ribosome.Genetic information is encoded in codons consisting of three bases each.Each codon encodes for a specific amino acid except the stop codonthat terminates the protein synthesis.
- 10. RibosomeThe ribosomes provides the structural site where the mRNA sits.Each tRNA has a nucleotide triplet which bonds to the complementary sequence o the mRNARibosomes 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 chainRibosomes are not one solid piece; they are made of two pieces or subunits.To make the protein, the two subunits of ribosome join together and combine with mRNA.The completed ribosome locks onto the mRNA and begins the process of protein biosynthesis.
- 12. ATPAdenosine-5-triphosphate is a multifunctional nucleotide used in cells as a coenzyme.ATP transports chemical energy within cells for metabolism.Energy for binding the amino acids to tRNA comes from the conversion of ATP to AMP.Mg2+Verstile mineral having major implicationsInvolved in 300 enzymatic reactions like glycolysis etc.Provides stability to ATP by forming magnesium:ATP complex.
- 14. Mg2+play an important role in protein biosynthesis.It is necessary for the activation of amino acid and for the attachment of mRNA to ribosome.Protein synthesis depend on the optimal concentration of Mg2+.Initiation FactorTheseare the proteins that bind to the small subunit of ribosome during the initiation of translationGTPSource of energy for protein synthesis.Used as energy source for binding the tRNA to A site of ribosome.Translocation of ribosme toward the mRNA
- 15. Elongation factorsSet of proteins that facilitates the events of translational elongation; the steps in protein synthesis from the formation of 1st peptide bond to the last.Stop codonStop codon or termination codon is a nucleotide triplet within mRNA that signals a termination of translation
- 16. UAG; UAA; UGA.Release factorsA protein that allows the termination by recognizing the termination codon in a mRNA sequence.Difference between prokeryotic and eukeryotic protein biosynthesisProkeryotesEukeryotesRibosome is 70s (30s and 40s subunits).Only a single functional site for the initiation of protein synthesis.Starting amino acid is N-formylmethionine.Initiation factors are IF1,IF2 and IF3.Elongation factors: EF-Tu, EF-Ts and EF-G.Release factors:RF-1 RF-2 and RF-3.Ribosome is 80s (40s and 60s).These are polycistronic and contain several initiation and termination sites.Starting amino acid is methionine.Main Initiation factor is IF1 and many more factors involved.Elongation factors: EF-1 and EF-2.Release factors: RF recognizes the termination site