Guanidine hydrochloride-induced unfolding of the three heme coordination states of the CO-sensing transcription factor, CooA.

ABSTRACT: CooA is a heme-dependent CO-sensing transcription factor that has three observable heme coordination states. There is some evidence that each CooA heme state has a distinct protein conformation; the goal of this study was to characterize these conformations by measuring their structural stabilities through guanidine hydrochloride (GuHCl) denaturation. By studying the denaturation processes of the Fe(III) state of WT CooA and several variants, we were able to characterize independent unfolding processes for each domain of CooA. This information was used to compare the unfolding profiles of various CooA heme activation states [Fe(III), Fe(II), and Fe(II)-CO] to show that the heme coordination state changes the stability of the effector binding domain. A mechanism consistent with the data pre

SUBMITTER: Lee AJ 

PROVIDER: S-EPMC2849680 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature