The three-spin intermediate at the O-O cleavage and proton-pumping junction in heme-Cu oxidases.

ABSTRACT: Understanding the mechanistic coupling of molecular oxygen reduction and proton pumping for adenosine triphosphate synthesis during cellular respiration is the primary goal of research on heme-copper oxidases—the terminal complex in the membrane-bound electron transport chain. Cleavage of the oxygen-oxygen bond by the heme-copper oxidases forms the key intermediate P_M, which initiates proton pumping. This intermediate is now experimentally defined by variable-temperature, variable-field magnetic circular dichroism spectroscopy on a previously unobserved excited state feature associated with its heme iron(IV)-oxo center. These data provide evidence that the iron(IV)-oxo in P_M is magnetically coupled to both a copper(II) and a cross-linked tyrosyl radical in the active

SUBMITTER: Jose A 

PROVIDER: S-EPMC9036946 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature