The asymmetry and cooperativity of tandem glycine riboswitch aptamers.

ABSTRACT: Glycine riboswitches utilize both single- and tandem-aptamer architectures. In the tandem system, the relative contribution of each aptamer toward gene regulation is not well understood. To dissect these contributions, the effects of 684 single mutants of a tandem ON switch from Bacillus subtilis were characterized for the wild-type construct and binding site mutations that selectively restrict ligand binding to either the first or second aptamer. Despite the structural symmetry of tandem aptamers, the response to these mutations was frequently asymmetrical. Mutations in the first aptamer often significantly weakened the K_1/2, while several mutations in the second aptamer improved the amplitude. These results demonstrate that this ON switch favors ligand binding to

SUBMITTER: Torgerson CD 

PROVIDER: S-EPMC7161355 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature