BIO130H1 Lecture Notes - Lecture 12: Aminoacyl-Trna, Aminoacyltransferase, World Federation Of Trade Unions

• School: UTSG
• Department: Biology
• Course: BIO130H1
• Professor: Melody Neumann

Document Summary

Overview of the catalytic process for amino acid addition. Presence of e, p and a sites on ribosomes. Energy stored in covalent bond between aa and trna in p position makes peptide synthesis energetically favourable. If h-bonding correct, gtp hydrolyzed and ef-tu released (as long as ef-tu is bound to trna, it cannot fit in the a site properly, therefore released) If h-bonding not correct, ef-tu (cid:374)ot (cid:396)eleased, gtp (cid:449)o(cid:374)"t (cid:271)e h(cid:455)d(cid:396)ol(cid:455)zed, peptide (cid:271)o(cid:374)d (cid:272)a(cid:374)"t fo(cid:396)(cid:373) Slight delay before formation of peptide bond allows one last check for accurate h-bonding (last chance for ribosome to make sure the right protein is being made) Can ribosomes perform protein synthesis without the aid of elongation factors: yes, but it is very slow. Improving speed and efficiency (ef-g in prokaryotes and ef2 in eukaryotes: error checking function (ef-tu in prokaryotes and ef1a in eukaryotes) These are mediated by the release of ef-tu, ef-g and gtp hydrolysis.