title: Characterization of bromoethanesulfonate-resistant mutants of Methanococcus voltae: evidence of a coenzyme M transport system.
abstract: Mutants of Methanococcus voltae were isolated that were resistant to the coenzyme M (CoM; 2-mercaptoethanesulfonic acid) analog 2-bromoethanesulfonic acid (BES). The mutants displayed a reduced ability to accumulate [35S]BES relative to the sensitive parental strain. BES inhibited methane production from CH3-S-CoM in cell extracts prepared from wild-type sensitive or resistant strains. BES uptake required the presence of both CO2 and H2 and was inhibited by N-ethylmaleimide and several reagents that are known to disrupt energy metabolism. The mutants showed normal uptake of isoleucine and were not cross-resistant to either azaserine or 5-methyltryptophan and, thus, were neither defective in general energy-dependent substrate transport nor envelope permeability. Both HS-CoM and CH3-S-CoM prevented the uptake of BES and protected cells from inhibition by it. We propose that M. voltae has an energy-dependent, carrier-mediated uptake system for HS-CoM and CH3-S-CoM which can also mediate uptake of BES.
mesh_terms: D000476:Alkanesulfonates / Q000378:metabolism / Q000494:pharmacology*; D017738:Alkanesulfonic Acids; D000596:Amino Acids / Q000378:metabolism; D001692:Biological Transport; D004352:Drug Resistance, Microbial; D005033:Ethylmaleimide / Q000494:pharmacology; D019605:Euryarchaeota / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008623:Mercaptoethanol / Q000031:analogs & derivatives*; D015080:Mesna / Q000378:metabolism*; D009154:Mutation; D010088:Oxidoreductases / Q000378:metabolism; D013045:Species Specificity
chemical_list: D000476:Alkanesulfonates; D017738:Alkanesulfonic Acids; D000596:Amino Acids; C018853:2-bromoethanesulfonic acid; D008623:Mercaptoethanol; D010088:Oxidoreductases; C023895:methyl coenzyme M methylreductase; D015080:Mesna; D005033:Ethylmaleimide