A single mutation at residue 25 populates the folding intermediate of E. coli RNase H and reveals a highly dynamic partially folded ensemble.

ABSTRACT: Understanding the nature of partially folded intermediates transiently populated during protein folding is important for understanding both protein folding and misfolding. These ephemeral species, however, often elude direct experimental characterization. The well-characterized protein ribonuclease H (RNase H) from Escherichia coli populates an on-pathway intermediate identified in both bulk studies and single-molecule mechanical unfolding experiments. Here, we set out to trap the transient intermediate of RNase H at equilibrium by selectively destabilizing the region of the protein known to be unfolded in this species. Surprisingly, a single change at Ile25 (I25A) resulted in the equilibrium population of the intermediate under near-native conditions. The intermediate was undetectable in

SUBMITTER: Connell KB 

PROVIDER: S-EPMC2881687 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature