Ribosome-catalyzed peptide-bond formation with an A-site substrate covalently linked to 23S ribosomal RNA.
In the ribosome, the aminoacyl-transfer RNA (tRNA) analog 4-thio-dT-p-C-p-puromycin crosslinks photochemically with G2553 of 23S ribosomal RNA (rRNA). This covalently linked substrate reacts with a peptidyl-tRNA analog to form a peptide bond in a peptidyl transferase-catalyzed reaction. This result places the conserved 2555 loop of 23S rRNA at the peptidyl transferase A site and suggests that peptide bond formation can occur uncoupled from movement of the A-site tRNA. Crosslink formation depends on occupancy of the P site by a tRNA carrying an intact CCA acceptor end, indicating that peptidyl-tRNA, directly or indirectly, helps to create the peptidyl transferase A site.
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Center for Molecular Biology of RNA, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064, USA.
Switzer
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Noller
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D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001665:Binding Sites; D002384:Catalysis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli; D009690:Nucleic Acid Conformation; D010458:Peptidyl Transferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011691:Puromycin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000378:metabolism*; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D012346:RNA, Transfer, Amino Acyl; D012360:RNA, Transfer, Phe; D011691:Puromycin; D010458:Peptidyl Transferases