Language
English
Publication Date
12-1-2019
Journal
Nature Structural & Molecular Biology
DOI
10.1038/s41594-019-0326-7
PMID
31740854
PMCID
PMC6899168
PubMedCentral® Posted Date
5-18-2020
PubMedCentral® Full Text Version
Author MSS
Abstract
Amino acid availability in Gram-positive bacteria is monitored by T-box riboswitches. T-boxes directly bind tRNAs, assess their aminoacylation state, and regulate the transcription or translation of downstream genes to maintain nutritional homeostasis. Here, we report cocrystal and cryo-EM structures of Geobacillus kaustophilus and Bacillus subtilis T-box-tRNA complexes, detailing their multivalent, exquisitely selective interactions. The T-box forms a U-shaped molecular vise that clamps the tRNA, captures its 3' end using an elaborate 'discriminator' structure, and interrogates its aminoacylation state using a steric filter fashioned from a wobble base pair. In the absence of aminoacylation, T-boxes clutch tRNAs and form a continuously stacked central spine, permitting transcriptional readthrough or translation initiation. A modeled aminoacyl disrupts tRNA-T-box stacking, severing the central spine and blocking gene expression. Our data establish a universal mechanism of amino acid sensing on tRNAs and gene regulation by T-box riboswitches and exemplify how higher-order RNA-RNA interactions achieve multivalency and specificity.
Keywords
Amino Acids, Aminoacylation, Bacillus subtilis, Cryoelectron Microscopy, Crystallography, X-Ray, Geobacillus, Models, Molecular, Nucleic Acid Conformation, RNA, Bacterial, RNA, Transfer, Riboswitch
Published Open-Access
yes
Recommended Citation
Li, Shuang; Su, Zhaoming; Lehmann, Jean; et al., "Structural basis of amino acid surveillance by higher-order tRNA-mRNA interactions" (2019). Faculty and Staff Publications. 133.
https://digitalcommons.library.tmc.edu/baylor_docs/133
Included in
Biology Commons, Medical Molecular Biology Commons, Medical Specialties Commons, Molecular Biology Commons