The torYZ (yecK bisZ) Operon Encodes a Third Respiratory Trimethylamine N-Oxide Reductase in Escherichia coli

AUTOR(ES)

Gon, Stéphanie

FONTE

American Society for Microbiology

RESUMO

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.

Documentos Relacionados

• The periplasmic TorT protein is required for trimethylamine N-oxide reductase gene induction in Escherichia coli.
• The torR gene of Escherichia coli encodes a response regulator protein involved in the expression of the trimethylamine N-oxide reductase genes.
• The torR gene of Escherichia coli encodes a response regulator protein involved in the expression of the trimethylamine N-oxide reductase genes.
• The narL gene product activates the nitrate reductase operon and represses the fumarate reductase and trimethylamine N-oxide reductase operons in Escherichia coli.
• Proton translocation coupled to trimethylamine N-oxide reduction in anaerobically grown Escherichia coli.