New tRNA contacts facilitate ligand binding in a Mycobacterium smegmatis T box riboswitch
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
T box riboswitches are RNA regulatory elements widely used by organisms in the phyla Firmicutes and Actinobacteria to regulate expression of amino acid-related genes. Expression of T box family genes is down-regulated by transcription attenuation or inhibition of translation initiation in response to increased charging of the cognate tRNA. Three direct contacts with tRNA have been described; however, one of these contacts is absent in a subclass of T box RNAs and the roles of several structural domains conserved in most T box RNAs are unknown. In this study, structural elements of a Mycobacterium smegmatis ileS T box riboswitch variant with an Ultrashort (US) Stem I were sequentially deleted, which resulted in a progressive decrease in binding affinity for the tRNAIle ligand. Selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) revealed structural changes in conserved riboswitch domains upon interaction with the tRNA ligand. Cross-linking and mutational analyses identified two interaction sites, one between the S-turn element in Stem II and the T arm of tRNAIle and the other between the Stem IIA/B pseudoknot and the D loop of tRNAIle. These newly identified RNA contacts add information about tRNA recognition by the T box riboswitch and demonstrate a role for the S-turn and pseudoknot elements, which resemble structural elements that are common in many cellular RNAs.
Originalsprog | Engelsk |
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Tidsskrift | Proceedings of the National Academy of Sciences of the United States of America |
Vol/bind | 115 |
Udgave nummer | 15 |
Sider (fra-til) | 3894-3899 |
Antal sider | 6 |
ISSN | 0027-8424 |
DOI | |
Status | Udgivet - 2018 |
Eksternt udgivet | Ja |
ID: 368624103