Molecular recognition of RhlB and RNase D in the Caulobacter crescentus RNA degradosome.
Voss, J.E., Luisi, B.F., Hardwick, S.W.(2014) Nucleic Acids Res 42: 13294-13305
- PubMed: 25389270
- DOI: https://doi.org/10.1093/nar/gku1134
- Primary Citation of Related Structures:
4OXP - PubMed Abstract:
The endoribonuclease RNase E is a key enzyme in RNA metabolism for many bacterial species. In Escherichia coli, RNase E contributes to the majority of RNA turnover and processing events, and the enzyme has been extensively characterized as the central component of the RNA degradosome assembly. A similar RNA degradosome assembly has been described in the α-proteobacterium Caulobacter crescentus, with the interacting partners of RNase E identified as the Kreb's cycle enzyme aconitase, a DEAD-box RNA helicase RhlB and the exoribonuclease polynucleotide phosphorylase. Here we report that an additional degradosome component is the essential exoribonuclease RNase D, and its recognition site within RNase E is identified. We show that, unlike its E. coli counterpart, C. crescentus RhlB interacts directly with a segment of the N-terminal catalytic domain of RNase E. The crystal structure of a portion of C. crescentus RNase E encompassing the helicase-binding region is reported. This structure reveals that an inserted segment in the S1 domain adopts an α-helical conformation, despite being predicted to be natively unstructured. We discuss the implications of these findings for the organization and mechanisms of the RNA degradosome.
Organizational Affiliation:
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.