Site-directed spin label electron paramagnetic resonance spectroscopy as a probe of conformational dynamics in the Fe(III) "locked-off" state of the CO-sensing transcription factor CooA.

ABSTRACT: The transcriptional activator CooA belongs to the CRP/FNR (cAMP receptor protein/fumarate and nitrate reductase) superfamily of transcriptional regulators and uses heme to sense carbon monoxide (CO). Effector-driven allosteric activation is well understood in CRP, a CooA homologue. A structural allosteric activation model for CooA exists which parallels that of CRP; however, the role of protein dynamics, which is crucial in CRP, is not well understood in CooA. We employed site-directed spin labeling electron paramagnetic resonance spectroscopy to probe CooA motions on the μs-ms timescale. We created a series of Cys substitution variants, each with a cysteine residue introduced into a key functional region of the protein: K26C, E60C, F132C, D134C, and S175C. The heme environment and DNA bin

SUBMITTER: Hines JP 

PROVIDER: S-EPMC6194275 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature