PMID: 15866937
Gutierrez P, Li Y, Osborne MJ, Pomerantseva E, Liu Q, Gehring K
Solution structure of the carbon storage regulator protein CsrA from Escherichia coli.
J Bacteriol. 2005 May;187(10):3496-501.
The carbon storage regulator A (CsrA) is a protein responsible for the repression of a variety of stationary-phase genes in bacteria. In this work, we describe the nuclear magnetic resonance (NMR)-based structure of the CsrA dimer and its RNA-binding properties. CsrA is a dimer of two identical subunits, each composed of five strands, a small alpha-helix and a flexible C terminus. NMR titration experiments suggest that the beta1-beta2 and beta3-beta4 loops and the C-terminal helix are important elements in RNA binding. Even though the beta3-beta4 loop contains a highly conserved RNA-binding motif, GxxG, typical of KH domains, our structure excludes CsrA from being a member of this protein family, as previously suggested. A mechanism for the recognition of mRNAs downregulated by CsrA is proposed.