The regulatory protein RraA modulates RNA-binding and helicase activities of the E. coli RNA degradosome.

Maria W Górna, Zbigniew Pietras, Yi-Chun Tsai, Anastasia J Callaghan, Helena Hernández, Carol V Robinson, Ben F Luisi

Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.

RNA (New York, N.Y.) 2010 Mar

filter terms:

The Escherichia coli endoribonuclease RNase E is an essential enzyme having key roles in mRNA turnover and the processing of several structured RNA precursors, and it provides the scaffold to assemble the multienzyme RNA degradosome. The activity of RNase E is inhibited by the protein RraA, which can interact with the ribonuclease's degradosome-scaffolding domain. Here, we report that RraA can bind to the RNA helicase component of the degradosome (RhlB) and the two RNA-binding sites in the degradosome-scaffolding domain of RNase E. In the presence of ATP, the helicase can facilitate the exchange of RraA for RNA stably bound to the degradosome. Our data suggest that RraA can affect multiple components of the RNA degradosome in a dynamic, energy-dependent equilibrium. The multidentate interactions of RraA impede the RNA-binding and ribonuclease activities of the degradosome and may result in complex modulation and rerouting of degradosome activity.

Citation

Maria W Górna, Zbigniew Pietras, Yi-Chun Tsai, Anastasia J Callaghan, Helena Hernández, Carol V Robinson, Ben F Luisi. The regulatory protein RraA modulates RNA-binding and helicase activities of the E. coli RNA degradosome. RNA (New York, N.Y.). 2010 Mar;16(3):553-62