The mechanism(s) of superoxide reduction by superoxide reductases in vitro and in vivo

Abstract

Exposure of obligately anaerobic bacteria and archaea to transiently aerobic or micro-aerobic growth habitats requires that these microorganisms protect against oxidative stress resulting from adventitious dioxygen reduction. Superoxide reductases (SORs), which catalyze reduction of superoxide to hydrogen peroxide, have been identified as one component of a novel oxidative stress protection system in anaerobic bacteria and archaea. SORs contain a unique non-heme [Fe(His)(4)(Cys)] active site. This Commentary addresses the mechanism of superoxide reduction catalyzed by this unique active site in SORs both in vitro and in vivo.