Structural insights into mRNA reading frame regulation by tRNA modification and slippery codon-anticodon pairing

• Type of Material: Article
• Authors: Eric D. Hoffer, Emory University; Samuel Hong, Emory University; S. Sunita, Emory University; Tatsuya Maehigashi, Emory University; Ruben L. Gonzalez, Jr., Columbia University; Paul C. Whitford, Northeastern University; Christine Dunham, Emory University
• Language: English
• Date: 2020-10-05
• Publisher: ELIFE SCIENCES PUBLICATIONS LTD
• Publication Version: Final Published Version
• Copyright Statement: © 2020, Hoffer et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.7554/eLife.51898
• Title of Journal or Parent Work: ELIFE
• Volume: 9
• Start Page: 1
• End Page: 20
• Grant/Funding Information: This work was supported by the NIH R01GM093278 (to CMD), NIH R01GM119386 (to RLG Jr), and NSF MCB-1915843 (PCW). CMD is a Burroughs Wellcome Fund Investigator in the Pathogenesis of Infectious Diseases. The X-ray crystallography datasets were collected at the Northeastern Collaborative Access Team (NE-CAT) and Southeast Regional Collaborative Access Team (SER-CAT) beamlines. At the NE-CAT beamlines (GM124165), a Pilatus detector (RR029205), and an Eiger detector (OD021527) were used. At SER-CAT, the beamlines is supported by its member institutions, and equipment grants (S10RR25528, S10RR028976 and S10OD027000) from the NIH. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357 (NE-CAT) and Contract No. W-31-109-Eng-38 (SER-CAT).
• Keywords: SUBUNIT; RIBOSOME; TRANSLATION; EF-P; Biology; Science & Technology; HEAD; SITE TRANSFER-RNA; STEM; MAINTENANCE; TRANSLOCATION; Life Sciences & Biomedicine; Life Sciences & Biomedicine - Other Topics; MOVEMENT
• Research Categories: Biology, Cell; Biology, Genetics

Abstract

Modifications in the tRNA anticodon loop, adjacent to the three-nucleotide anticodon, influence translation fidelity by stabilizing the tRNA to allow for accurate reading of the mRNA genetic code. One example is the N1-methylguanosine modification at guanine nucleotide 37 (m1G37) located in the anticodon loop andimmediately adjacent to the anticodon nucleotides 34, 35, 36. The absence of m1G37 in tRNAPro causes +1 frameshifting on polynucleotide, slippery codons. Here, we report structures of the bacterial ribosome containing tRNAPro bound to either cognate or slippery codons to determine how the m1G37 modification prevents mRNA frameshifting. The structures reveal that certain codon–anticodon contexts and the lack of m1G37 destabilize interactions of tRNAPro with the P site of the ribosome, causing large conformational changes typically only seen during EF-G-mediated translocation of the mRNA-tRNA pairs. These studies provide molecular insights into how m1G37 stabilizes the interactions of tRNAPro with the ribosome in the context of a slippery mRNA codon.