B12 cofactors directly stabilize an mRNA regulatory switch.

ABSTRACT: Structures of riboswitch receptor domains bound to their effector have shown how messenger RNAs recognize diverse small molecules, but mechanistic details linking the structures to the regulation of gene expression remain elusive. To address this, here we solve crystal structures of two different classes of cobalamin (vitamin B(12))-binding riboswitches that include the structural switch of the downstream regulatory domain. These classes share a common cobalamin-binding core, but use distinct peripheral extensions to recognize different B(12) derivatives. In each case, recognition is accomplished through shape complementarity between the RNA and cobalamin, with relatively few hydrogen bonding interactions that typically govern RNA-small molecule recognition. We show that a composite cobala

SUBMITTER: Johnson JE 

PROVIDER: S-EPMC3518761 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature