Publications

• Multiple pathways of electron transfer in dimethyl sulfoxide reductase of Escherichia coli.

  Trieber C.A., Rothery R.A., Weiner J.H.

  The catalytic subunit of dimethyl sulfoxide (Me2SO) reductase, DmsA, contains six blocks of sequence that are homologous to other members of the superfamily of prokaryotic molybdoenzymes. The amino-terminal block contains 5 conserved residues (Cys38, Cys42, Cys75, Lys28, and Arg77). Site-directed ... >> More

  The catalytic subunit of dimethyl sulfoxide (Me2SO) reductase, DmsA, contains six blocks of sequence that are homologous to other members of the superfamily of prokaryotic molybdoenzymes. The amino-terminal block contains 5 conserved residues (Cys38, Cys42, Cys75, Lys28, and Arg77). Site-directed mutagenesis of these residues did not alter membrane localization but in some cases less enzyme accumulated. The activity of Me2SO reductase was monitored by measuring Me2SO-dependent anaerobic growth, benzyl viologen, or dimethylnaphthoquinol oxidase activity, and using a quinol pool-coupling assay. Only Cys75 and Lys28 mutant enzymes were able to support anaerobic growth with Me2SO suggesting a critical role for Cys38, Cys42, and Arg77. Benzyl viologen oxidase activity was retained in the mutants although with reduced efficiency in Cys42-Ser. Electron transport with dimethylnaphthoquinol was reduced in Cys38-Ser, Cys42-Ser, and Cys75-Ser and almost totally eliminated in the Arg77-Ser mutant. Cys38-Ser, Cys42-Ser, and Arg77-Ser were unable to support quinol oxidation although electron transfer from the quinol pool to the [Fe-S] centers in DmsB was normal. These results indicate that the amino-terminal region is involved in functional electron transfer from the quinol pool to Me2SO and that electrons from benzyl viologen, dimethylnaphthoquinol, and menaquinol may follow different paths within the catalytic subunit. << Less

  J. Biol. Chem. 269:7103-7109(1994) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• The torYZ (yecK bisZ) operon encodes a third respiratory trimethylamine N-oxide reductase in Escherichia coli.

  Gon S., Patte J.-C., Mejean V., Iobbi-Nivol C.

  The bisZ gene of Escherichia coli was previously described as encoding a minor biotin sulfoxide (BSO) reductase in addition to the main cytoplasmic BSO reductase, BisC. In this study, bisZ has been renamed torZ based on the findings that (i) the torZ gene product, TorZ, is able to reduce trimethyl ... >> More

  The bisZ gene of Escherichia coli was previously described as encoding a minor biotin sulfoxide (BSO) reductase in addition to the main cytoplasmic BSO reductase, BisC. In this study, bisZ has been renamed torZ based on the findings that (i) the torZ gene product, TorZ, is able to reduce trimethylamine N-oxide (TMAO) more efficiently than BSO; (ii) although TorZ is more homologous to BisC than to the TMAO reductase TorA (63 and 42% identity, respectively), it is located mainly in the periplasm as is TorA; (iii) torZ belongs to the torYZ operon, and the first gene, torY (formerly yecK), encodes a pentahemic c-type cytochrome homologous to the TorC cytochrome of the TorCAD respiratory system. Furthermore, the torYZ operon encodes a third TMAO respiratory system, with catalytic properties that are clearly different from those of the TorCAD and the DmsABC systems. The torYZ and the torCAD operons may have diverged from a common ancestor, but, surprisingly, no torD homologue is found in the sequences around torYZ. Moreover, the torYZ operon is expressed at very low levels under the conditions tested, and, in contrast to torCAD, it is not induced by TMAO or dimethyl sulfoxide. << Less

  J. Bacteriol. 182:5779-5786(2000) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.