Dynamic competition of DsrA and rpoS fragments for the proximal binding site of Hfq as a means for efficient annealing.

ABSTRACT: Hfq is a key regulator involved in multiple aspects of stress tolerance and virulence of bacteria. There has been an intriguing question as to how this RNA chaperone achieves two completely opposite functions--annealing and unwinding--for different RNA substrates. To address this question, we studied the Hfq-mediated interaction of fragments of a non-coding RNA, DsrA, with its mRNA target rpoS by using single-molecule fluorescence techniques. These experiments permitted us to observe the mechanistic steps of Hfq-mediated RNA annealing/unwinding at the single-molecule level, for the first time. Our real-time observations reveal that, even if the ring-shaped Hfq displays multiple binding sites for its interaction with RNA, the regulatory RNA and the mRNA compete for the same binding site. Th

SUBMITTER: Hwang W 

PROVIDER: S-EPMC3130260 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature