Gene Structure and Expression Profile of CytochromebcNitric Oxide Reductase fromHydrogenobacter thermophilusTK-6

Miho SUZUKI, Hiroyuki ARAI, Masaharu ISHII, Yasuo IGARASHI
2006 Bioscience, biotechnology and biochemistry  
The genes for a nitric oxide reductase-like cytochrome bc complex were cloned from a thermophilic, chemolithoautotrophic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6. The structural genes norC and norB, which encode cytochrome c and cytochrome b subunits of the complex respectively, are probably transcribed as a tricistronic operon with a following gene encoding a putative membrane protein. NorC has, unusually, two hydrophobic transmembrane spans in its N-terminus. Immunoblot
more » ... analysis showed that expression of NorC was induced by nitrate, nitrite, or sodium nitropurusside, suggesting that the norCB gene product is a denitrification enzyme, nitric oxide reductase. The consensus sequences for the DNR/NnrRtype or the NorR/FhpR-type nitric oxide-sensing regulators of proteobacteria were not found in the norC promoter region, but consensus À35 and À10 sequences were found in this region. These results indicate that strain TK-6 has a nitrogen oxide-sensing regulatory system that differs from proteobacterial systems.
doi:10.1271/bbb.60018 pmid:16861801 fatcat:gitlvfdkpvbqjdn7sablp62i5i