The Reactions of O2 and NO with Mixed-Valence ba3 Cytochrome c Oxidase from Thermus thermophilus (Biophysical Journal)

Earlier CO flow-flash experiments on the fully reduced Thermus thermophilus ba3 (Tt ba3) cytochrome oxidase revealed that O2 binding was slowed down by a factor of 10 in the presence of CO (Szundi et al., 2010, PNAS 107, 21010-21015). The goal of the current study is to explore whether the long apparent lifetime (~50 ms) of the CuB+-CO complex generated upon photolysis of the CO-bound mixed-valence Tt ba3 (Koutsoupakis et al., 2019, Acc. Chem. Res. 52, 1380-1390) affects O2 and NO binding and the ability of CuB to act as an electron donor during O-O bond splitting.