BIOC 406 Lecture Notes - Lecture 21: Peptidyl Transferase, Integral Membrane Protein, Protein Precursor
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Example: before running reaction he put in proteases that would denature the protein activity of the ribosome. He then put in a ribonuclease and it totally killed the activity. At the peptidyl transfer site there is no protein, it is only the rna part doing the catalysis. Puromycin binds ptc, inhibits peptidyl transfer reaction and blocks exit tunnel. Termination: stop codon bacteria have release factors that bind to the stop codon, water hydrolyzes the chain and it drifts off (termination release factors are shaped like trna!) Ef-g cooperates with release factors and they hydrolyze gtp, which is used as a signal to disassemble the structure (large from small). Initiation factors will bind to the small subunit so the large subunit won"t bind yet. How much does it cost to make a peptide bond? at least 4 high-energy phosphates per peptide bond. 122 kj/mol free-energy released free-energy of peptide bond 21 kj/mol net free energy change = -100 kj/mol.
