Summary information and primary citation
- PDB-id
- 6pmo; DSSR-derived features in text and JSON formats
- Class
- RNA
- Method
- X-ray (2.66 Å)
- Summary
- Co-crystal structure of the geobacillus kaustophilus glyq t-box riboswitch discriminator domain in complex with trna-gly
- Reference
- Li S, Su Z, Lehmann J, Stamatopoulou V, Giarimoglou N, Henderson FE, Fan L, Pintilie GD, Zhang K, Chen M, Ludtke SJ, Wang YX, Stathopoulos C, Chiu W, Zhang J (2019): "Structural basis of amino acid surveillance by higher-order tRNA-mRNA interactions." Nat.Struct.Mol.Biol., 26, 1094-1105. doi: 10.1038/s41594-019-0326-7.
- 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.