Entropic Control of an Excited Folded-Like Conformation in a Disordered Protein Ensemble.

ABSTRACT: Many intrinsically disordered proteins switch between unfolded and folded-like forms in the presence of their binding partner. The possibility of a pre-equilibrium between the two macrostates is challenging to discern given the complex conformational landscape. Here, we show that CytR, a disordered DNA-binding domain, samples a folded-like excited state in its native ensemble through equilibrium multi-probe spectroscopy, kinetics and an Ising-like statistical mechanical model. The population of the excited state increases upon stabilization of the native ensemble with an osmolyte, while decreasing with increasing temperatures. A conserved proline residue, the mutation of which weakens the binding affinity to the target promoter, is found to uniquely control the population of the minor exci

SUBMITTER: Munshi S 

PROVIDER: S-EPMC6166778 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature