Lecture 50 - Lecture 50 Translation(protein synthesis Flow of genetic information the"Central Dogma DNA Replication Transcription RNA Translation

1 tRNA (provides amino acids) Ribosome (complex of rRNA and proteins where tranlation occurs) Flow of genetic information --- the “Central Dogma” DNA RNA Protein Replication Transcription Translation mRNA (primary sequence) Lecture 50: Translation (protein synthesis) Today’s lecture: Text pp. 1027-1044 Preprinted lecture notes 76-85 Download from http://biochem.med.ufl.edu/coursetemp.php?cid=44 or http://www.mbi.ufl.edu/facilities/msg/bch4024-notes.html tRNA is the adaptor molecule for RNA Æ amino acid ¾ Each tRNA contains a nucleotide triplet or “anti codon” complimentary to the mRNA for a particular amino acid ¾ Aminoacyl-tRNA synthetase attaches a particular tRNA to its corresponding amino acid ¾ tRNA has extensive self- complimentarity and is much more stable than mRNA Phenylalanine tRNA

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2 Protein synthesis: activation of amino acids a) Aminoacyl-tRNA synthetase binds amino acid + ATP to yield enzyme-bound adenylated amino acid b) tRNA binds to the adenylated a.a.- synthetase complex and the amino acid is transferred to the 2’ or 3’ OH of the 3’-terminal residue of the tRNA c) Activation…. The ester bond in aatRNA has a free energy of hydrolysis ~ ATP terminal PO 4 d) Requisite specificity of aatRNA synthetases 1) for tRNA (>20) 2) for amino acid (~20) ∴