New tRNA contacts facilitate ligand binding in a Mycobacterium smegmatis T box riboswitch.

ABSTRACT: 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 tRNA^Ile lig

SUBMITTER: Sherwood AV 

PROVIDER: S-EPMC5899468 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature