Ligand binding by the tandem glycine riboswitch depends on aptamer dimerization but not double ligand occupancy.

ABSTRACT: The glycine riboswitch predominantly exists as a tandem structure, with two adjacent, homologous ligand-binding domains (aptamers), followed by a single expression platform. The recent identification of a leader helix, the inclusion of which eliminates cooperativity between the aptamers, has reopened the debate over the purpose of the tandem structure of the glycine riboswitch. An equilibrium dialysis-based assay was combined with binding-site mutations to monitor glycine binding in each ligand-binding site independently to understand the role of each aptamer in glycine binding and riboswitch tertiary interactions. A series of mutations disrupting the dimer interface was used to probe how dimerization impacts ligand binding by the tandem glycine riboswitch. While the wild-type tandem ribos

SUBMITTER: Ruff KM 

PROVIDER: S-EPMC4201829 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature