Spectroscopic observation of RNA chaperone activities of Hfq in post-transcriptional regulation by a small non-coding RNA

摘要: Hfq protein is vital for the function of many non-coding small (s)RNAs in bacteria but mechanism by which facilitates sRNA still debated. We developed a fluorescence resonance energy transfer assay to probe how modulates interaction between sRNA, DsrA, and its regulatory target mRNA, rpoS. The relevant RNA fragments were labelled so that changes intra- intermolecular structures can be monitored real time. Our data show promotes strand exchange reaction internal structure rpoS replaced pairing with DsrA such Shine-Dalgarno sequence mRNA becomes exposed. appears carry out inducing rapid association premelted aiding slow disruption secondary structure. Unexpectedly, also disrupts preformed complex DsrA. While it may not frequent event vivo, this melting activity have implications reversal sRNA-based regulation. Overall, our suggests only binding rapidly both possesses chaperoning properties dynamic RNA-RNA interactions.