Effects of mutations in active site heme ligands on the spectroscopic and catalytic properties of SoxAX cytochromes

SoxAX cytochromes mediate the formation of heterodisulfide bonds by an unknown mechanism. Using substituted SoxAX proteins we have shown that catalysis likely involves a ligand switch on the catalytic SoxA heme, and both the ligands to the SoxA heme and the nearby Cu centre influence the SoxAX catalytic parameters.190