title: The regulatory protein RraA modulates RNA-binding and helicase activities of the E. coli RNA degradosome.
abstract: 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.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
authors.forename: Maria W
authors.initials: MW
authors.lastname: Górna
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Pietras
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Tsai
authors.forename: Anastasia J
authors.initials: AJ
authors.lastname: Callaghan
authors.forename: Helena
authors.initials: H
authors.lastname: Hernández
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
authors.forename: Ben F
authors.initials: BF
authors.lastname: Luisi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; C477942:RraA protein, E coli; C111244:degradosome; D000255:Adenosine Triphosphate; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C022537:ribonuclease E; C502431:RhlB protein, E coli; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases