A Transient, Excited Species of the Autoinhibited α-State of the Bacterial Transcription Factor RfaH May Represent an Early Intermediate on the Fold-Switching Pathway.

ABSTRACT: RfaH is a two-domain transcription factor in which the C-terminal domain switches fold from an α-helical hairpin to a β-roll upon binding the ops-paused RNA polymerase. To ascertain the presence of a sparsely populated excited state that may prime the autoinhibited resting state of RfaH for binding ops-paused RNA polymerase, we carried out a series of NMR-based exchange experiments to probe for conformational exchange on the millisecond time scale. Quantitative analysis of these data reveals exchange between major ground (∼95%) and sparsely populated excited (∼5%) states with an exchange lifetime of ∼3 ms involving residues at the interface between the N-terminal and C-terminal domains formed by the β3/β4 hairpin and helix α3 of the N-terminal domain and helices α4 and α5 of

SUBMITTER: Cai M 

PROVIDER: S-EPMC11345854 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature