Download MendeleyStructural basis of ligand binding by a c-di-GMP riboswitch.
Smith, K.D., Lipchock, S.V., Ames, T.D., Wang, J., Breaker, R.R., Strobel, S.A.(2009) Nat Struct Mol Biol 16: 1218-1223
- PubMed: 19898477
- DOI: https://doi.org/10.1038/nsmb.1702
- Primary Citation of Related Structures:
3IRW - PubMed Abstract:
The second messenger signaling molecule bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates many processes in bacteria, including motility, pathogenesis and biofilm formation. c-di-GMP-binding riboswitches are important downstream targets in this signaling pathway. Here we report the crystal structure, at 2.7 A resolution, of a c-di-GMP riboswitch aptamer from Vibrio cholerae bound to c-di-GMP, showing that the ligand binds within a three-helix junction that involves base-pairing and extensive base-stacking. The symmetric c-di-GMP is recognized asymmetrically with respect to both the bases and the backbone. A mutant aptamer was engineered that preferentially binds the candidate signaling molecule c-di-AMP over c-di-GMP. Kinetic and structural data suggest that genetic regulation by the c-di-GMP riboswitch is kinetically controlled and that gene expression is modulated through the stabilization of a previously unidentified P1 helix, illustrating a direct mechanism for c-di-GMP signaling.
Organizational Affiliation:
Department of Chemistry, Yale University, New Haven, Connecticut, USA.
