Single-molecule force spectroscopy of the add adenine riboswitch relates folding to regulatory mechanism.

ABSTRACT: Riboswitches regulate gene expression via ligand binding to an aptamer domain which induces conformational changes in a regulatory expression platform. By unfolding and refolding single add adenine riboswitch molecules in an optical trap, an integrated picture of the folding was developed and related to the regulatory mechanism. Force-extension curves (FECs) and constant-force folding trajectories measured on the aptamer alone revealed multiple partially-folded states, including several misfolded states not on the native folding pathway. All states were correlated to key structural components and interactions within hierarchical folding pathways. FECs of the full-length riboswitch revealed that the thermodynamically stable conformation switches upon ligand binding from a structure repressi

SUBMITTER: Neupane K 

PROVIDER: S-EPMC3177178 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature