BIOL 1090 Lecture Notes - Lecture 9: Puromycin, Signal Recognition Particle, Translocon
26 Aug 2017
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Document Summary
The aminoacyl-trna in the a-site functions as the acceptor for the growing protein during peptide bond formation: p site: the ribosomal site most frequently occupied by peptidyl-trna, i. e. the trna carrying the growing peptide chain. The p-site is also referred to as the puromycin sensitive site. Puromycin is an antibiotic which shows similarities with a part of aminoacyl-trna. When puromycin is present in the a-site, the peptide can be linked to puromycin via a peptide bond. Thus, peptidyl- trna in the p-site is located in the puromycin sensitive site: e site: the ribosomal site harbouring decylated trna on transit out from the ribosome. Bulky proteins remain stuck in the er lumen simply b/c of size. Retrieval of escaped proteins: retrieval signals: presence of short amino acid sequences at the c-terminus signals the er to retrieve and keep the protein in the er.
