Crystal Structures of EF-G-Ribosome Complexes Trapped in Intermediate States of Translocation

Journal Article · Tue Nov 12 00:00:00 EST 2013 · Science

DOI:https://doi.org/10.1126/science.1236086· OSTI ID:1097291

Zhou, Jie; Lancaster, Laura; Donohue, John Paul; Noller, Harry F. ^[1]

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1. UCSC

Translocation of messenger and transfer RNA (mRNA and tRNA) through the ribosome is a crucial step in protein synthesis, whose mechanism is not yet understood. The crystal structures of three Thermus ribosome-tRNA-mRNA–EF-G complexes trapped with β,γ-imidoguanosine 5'-triphosphate (GDPNP) or fusidic acid reveal conformational changes occurring during intermediate states of translocation, including large-scale rotation of the 30S subunit head and body. In all complexes, the tRNA acceptor ends occupy the 50S subunit E site, while their anticodon stem loops move with the head of the 30S subunit to positions between the P and E sites, forming chimeric intermediate states. Two universally conserved bases of 16S ribosomal RNA that intercalate between bases of the mRNA may act as “pawls” of a translocational ratchet. These findings provide new insights into the molecular mechanism of ribosomal translocation.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: National Institutes of Health (NIH)
• OSTI ID: 1097291
• Journal Information: Science, Vol. 340, Issue 06, 2013; ISSN 0036-8075
• Publisher: AAAS
• Country of Publication: United States
• Language: ENGLISH