Abstract C-type heme-copper oxidases terminate the respiratory chain in many pathogenic bacteria, and will encounter elevated concentrations of NO produced by the immune defense of the host. Thus, a decreased sensitivity to NO in C-type oxidases would increase the survival of these pathogens. Here we have compared the inhibitory effect of NO in C-type oxidases to that in the mitochondrial A-type. We show that O2-reduction in both the Rhodobacter sphaeroides and Vibrio cholerae C-type oxidases is strongly and reversibly inhibited by submicromolar NO, with an inhibition pattern similar to the A-type. Thus, NO tolerance in pathogens with a C-type terminal oxidase has to rely mainly on other mechanisms.
Arjona, D., Wikström, M., & Ädelroth, P. (2015). Nitric oxide is a potent inhibitor of the cbb3-type heme-copper oxidases. FEBS Letters, 589(11), 1214–1218. https://doi.org/10.1016/j.febslet.2015.03.033