A Novel Mechanism of Reduction of Dimethyl Sulfoxide

Abstract

To date, a variety of microbes are known to grow by respiration with dimethyl sulfoxide (DMSO) as an electron acceptor. Several bacteria, such as Escherichia coli and Rhodopseudomonas capsula, have been characterized on DMSO respiratory systems consisted of electron carriers and a terminal DMSO reductase. In this study, we presented that cysteine-cystine redox shuttle serves as an electron mediator for DMSO reduction. Our experimental results show that thioredoxin reductase-protein disulfide oxidoreductase redox couple has a potential suitable for catalyzing the reduction of cystine to cysteine, permitting recycle of cysteine. Based on this mechanism of growth stimulation by DMSO via a redox-regulating system and an extracellular electron mediator, DMSO reduction is proposed to function simply by disposing of excess reducing power rather than conserving energy.tems consisted of electron carriers and a terminal DMSO reductase. In this study, we presented that cysteine-cystine redox shuttle serves as an electron mediator for DMSO reduction. Our experimental results show that thioredoxin reductase-protein disulfide oxidoreductase redox couple has a potential suitable for catalyzing the reduction of cystine to cysteine, permitting recycle of cysteine. Based on this mechanism of growth stimulation by DMSO via a redox-regulating system and an extracellular electron mediator, DMSO reduction is proposed to function simply by disposing of excess reducing power rather than conserving energy.