Title Dimethyl sulfoxide reduction by a hyperhermophilic archaeon Thermococcus onnurineus NA1 via a cysteine-cystine redox shuttle
Author Ae Ran Choi1, Min-Sik Kim1, Sung Gyun Kang1,2, and Hyun Sook Lee1,2*
Address 1Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan 15627, Republic of Korea, 2Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
Bibliography Journal of Microbiology, 54(1),31-38, 2016,
DOI 10.1007/s12275-016-5574-1
Key Words DMSO, Thermococcus onnurineus NA1, cysteinecystine redox shuttle, thioredoxin reductase, protein disulfide oxidoreductase, extracellular electron mediator
Abstract A variety of microbes grow by respiration with dimethyl sulfoxide (DMSO) as an electron acceptor, and several distinct DMSO respiratory systems, consisting of electron carriers and a terminal DMSO reductase, have been characterized. The heterotrophic growth of a hyperthermophilic archaeon Thermococcus onnurineus NA1 was enhanced by the addition of DMSO, but the archaeon was not capable of reducing DMSO to DMS directly using a DMSO reductase. Instead, the archaeon reduced DMSO via a cysteine-cystine redox shuttle through a mechanism whereby cystine is microbially reduced to cysteine, which is then reoxidized by DMSO reduction. A thioredoxin reductase-protein disulfide oxidoreductase redox couple was identified to have intracellular cystine-reducing activity, permitting recycle of cysteine. This study presents the first example of DMSO reduction via an electron shuttle. Several Thermococcales species also exhibited enhanced growth coupled with DMSO reduction, probably by disposing of excess reducing power rather than conserving energy.