Publications

• Structural basis of biological NO generation by octaheme oxidoreductases.

  Maalcke W.J., Dietl A., Marritt S.J., Butt J.N., Jetten M.S., Keltjens J.T., Barends T.R., Kartal B.

  Nitric oxide is an important molecule in all domains of life with significant biological functions in both pro- and eukaryotes. Anaerobic ammonium-oxidizing (anammox) bacteria that contribute substantially to the release of fixed nitrogen into the atmosphere use the oxidizing power of NO to activa ... >> More

  Nitric oxide is an important molecule in all domains of life with significant biological functions in both pro- and eukaryotes. Anaerobic ammonium-oxidizing (anammox) bacteria that contribute substantially to the release of fixed nitrogen into the atmosphere use the oxidizing power of NO to activate inert ammonium into hydrazine (N2H4). Here, we describe an enzyme from the anammox bacterium Kuenenia stuttgartiensis that uses a novel pathway to make NO from hydroxylamine. This new enzyme is related to octaheme hydroxylamine oxidoreductase, a key protein in aerobic ammonium-oxidizing bacteria. By a multiphasic approach including the determination of the crystal structure of the K. stuttgartiensis enzyme at 1.8 Å resolution and refinement and reassessment of the hydroxylamine oxidoreductase structure from Nitrosomonas europaea, both in the presence and absence of their substrates, we propose a model for NO formation by the K. stuttgartiensis enzyme. Our results expand the understanding of the functions that the widespread family of octaheme proteins have. << Less

  J. Biol. Chem. 289:1228-1242(2014) [PubMed] [EuropePMC]

• Studies of the hydroxylamine metabolism of Nitrosomonas europaea. I. Purification of hydroxylamine oxidase.

  Rees M.K.

  Biochemistry 7:353-366(1968) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Hydroxylamine oxidoreductase of Nitrosomonas. Production of nitric oxide from hydroxylamine.

  Hooper A.B., Terry K.R.

  Biochim. Biophys. Acta 571:12-20(1979) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Transcription of nitrification genes by the methane-oxidizing bacterium, Methylococcus capsulatus strain Bath.

  Poret-Peterson A.T., Graham J.E., Gulledge J., Klotz M.G.

  Methylococcus capsulatus strain Bath, a methane-oxidizing bacterium, and ammonia-oxidizing bacteria (AOB) carry out the first step of nitrification, the oxidation of ammonia to nitrite, through the intermediate hydroxylamine. AOB use hydroxylamine oxidoreductase (HAO) to produce nitrite. M. capsul ... >> More

  Methylococcus capsulatus strain Bath, a methane-oxidizing bacterium, and ammonia-oxidizing bacteria (AOB) carry out the first step of nitrification, the oxidation of ammonia to nitrite, through the intermediate hydroxylamine. AOB use hydroxylamine oxidoreductase (HAO) to produce nitrite. M. capsulatus Bath was thought to oxidize hydroxylamine with cytochrome P460 (cytL), until the recent discovery of an hao gene in its genome. We used quantitative PCR analyses of cDNA from M. capsulatus Bath incubated with CH(4) or CH(4) plus 5 mM (NH(4))(2)SO(4) to determine whether cytL and hao transcript levels change in response to ammonia. While mRNA levels for cytL were not affected by ammonia, hao mRNA levels increased by 14.5- and 31-fold in duplicate samples when a promoter proximal region of the transcript was analyzed, and by sixfold when a region at the distal end of the transcript was analyzed. A conserved open reading frame, orf2, located 3' of hao in all known AOB genomes and in M. capsulatus Bath, was cotranscribed with hao and showed increased mRNA levels in the presence of ammonia. These data led to designating this gene pair as haoAB, with the role of haoB still undefined. We also determined mRNA levels for additional genes that encode proteins involved in N-oxide detoxification: cytochrome c'-beta (CytS) and nitric oxide (NO) reductase (NorCB). Whereas cytS mRNA levels increased in duplicate samples by 28.5- and 40-fold in response to ammonia, the cotranscribed norC-norB mRNA did not increase. Our results strongly suggest that M. capsulatus Bath possesses a functional, ammonia-responsive HAO involved in nitrification. << Less

  ISME J 2:1213-1220(2008) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.