Download MendeleyRecognition of the bacterial second messenger cyclic diguanylate by its cognate riboswitch.
Kulshina, N., Baird, N.J., Ferre-D'Amare, A.R.(2009) Nat Struct Mol Biol 16: 1212-1217
- PubMed: 19898478
- DOI: https://doi.org/10.1038/nsmb.1701
- Primary Citation of Related Structures:
3IWN - PubMed Abstract:
The cyclic diguanylate (bis-(3'-5')-cyclic dimeric guanosine monophosphate, c-di-GMP) riboswitch is the first known example of a gene-regulatory RNA that binds a second messenger. c-di-GMP is widely used by bacteria to regulate processes ranging from biofilm formation to the expression of virulence genes. The cocrystal structure of the c-di-GMP responsive GEMM riboswitch upstream of the tfoX gene of Vibrio cholerae reveals the second messenger binding the RNA at a three-helix junction. The two-fold symmetric second messenger is recognized asymmetrically by the monomeric riboswitch using canonical and noncanonical base-pairing as well as intercalation. These interactions explain how the RNA discriminates against cyclic diadenylate (c-di-AMP), a putative bacterial second messenger. Small-angle X-ray scattering and biochemical analyses indicate that the RNA undergoes compaction and large-scale structural rearrangement in response to ligand binding, consistent with organization of the core three-helix junction of the riboswitch concomitant with binding of c-di-GMP.
Organizational Affiliation:
Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, USA.
