A third subunit in ancestral cytochrome c-dependent nitric oxide reductases

C. Bricio, L. Alvarez, M. San Martin, L. A. Schurig-Briccio, R. B. Gennis, J. Berenguer

Research output: Contribution to journalArticlepeer-review


Reduction of NO to N2O by denitrifiying bacteria is catalyzed either by a monomeric quinol-nitric oxide reductase (qNor) or by a heterodimeric cytochrome c-dependent nitric oxide reductase (cNor). In ancient thermophilic bacteria belonging to the Thermales and Aquificales phylogenetic groups, the cluster encoding the cNor includes a small third gene (norH), in addition to those encoding homologues to the subunits of a typical cNor (norC and norB). We show in Thermus thermophilus that the three genes are cotranscribed in a single mRNA from an inducible promoter. The isolation of individual nor mutants and the production in vivo of His-tagged NorH protein followed by immobilized-metal affinity chromatography (IMAC) allowed us to conclude that NorH constitutes a third subunit of the cNor from T. thermophilus, which is involved in denitrification in vivo, likely allowing more efficient electron transport to cNor.

Original languageEnglish (US)
Pages (from-to)4871-4878
Number of pages8
JournalApplied and environmental microbiology
Issue number16
StatePublished - Aug 2014

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

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