Compound I Formation and Reactivity in Dimeric Chlorite Dismutase: Impact of pH and the Dynamics of the Catalytic Arginine.

ABSTRACT: The heme enzyme chlorite dismutase (Cld) catalyzes the degradation of chlorite to chloride and dioxygen. Many questions about the molecular reaction mechanism of this iron protein have remained unanswered, including the electronic nature of the catalytically relevant oxoiron(IV) intermediate and its interaction with the distal, flexible, and catalytically active arginine. Here, we have investigated the dimeric Cld from Cyanothece sp. PCC7425 (CCld) and two variants having the catalytic arginine R127 (i) hydrogen-bonded to glutamine Q74 (wild-type CCld), (ii) arrested in a salt bridge with a glutamate (Q74E), or (iii) being fully flexible (Q74V). Presented stopped-flow spectroscopic studies demonstrate the initial and transient appearance of Compound I in the reaction b

SUBMITTER: Schmidt D 

PROVIDER: S-EPMC9910045 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature