A SAM-I riboswitch with the ability to sense and respond to uncharged initiator tRNA.

ABSTRACT: All known riboswitches use their aptamer to senese one metabolite signal and their expression platform to regulate gene expression. Here, we characterize a SAM-I riboswitch (SAM-I_Xcc) from the Xanthomonas campestris that regulates methionine synthesis via the met operon. In vitro and in vivo experiments show that SAM-I_Xcc controls the met operon primarily at the translational level in response to cellular S-adenosylmethionine (SAM) levels. Biochemical and genetic data demonstrate that SAM-I_Xcc expression platform not only can repress gene expression in response to SAM binding to SAM-I_Xcc aptamer but also can sense and bind uncharged initiator Met tRNA, resulting in the sequestering of the anti-Shine-Dalgarno (SD) sequence and freeing the SD for t

SUBMITTER: Tang DJ 

PROVIDER: S-EPMC7270179 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature