Physiological role of the respiratory quinol oxidase in the anaerobic nitrite-reducing methanotroph 'Candidatus Methylomirabilis oxyfera'.
The anaerobic nitrite-reducing methanotroph 'Candidatus Methylomirabilis oxyfera' ('Ca. M. oxyfera') produces oxygen from nitrite by a novel pathway. The major part of the O(2) is used for methane activation and oxidation, which proceeds by the route well known for aerobic methanotrophs. Residual oxygen may serve other purposes, such as respiration. We have found that the genome of 'Ca. M. oxyfera' harbours four sets of genes encoding terminal respiratory oxidases: two cytochrome c oxidases, a third putative bo-type ubiquinol oxidase, and a cyanide-insensitive alternative oxidase. Illumina sequencing of reverse-transcribed total community RNA and quantitative real-time RT-PCR showed that all four sets of genes were transcribed, albeit at low levels. Oxygen-uptake and inhibition experiments, UV-visible absorption spectral characteristics and EPR spectroscopy of solubilized membranes showed that only one of the four oxidases is functionally produced by 'Ca. M. oxyfera', notably the membrane-bound bo-type terminal oxidase. These findings open a new role for terminal respiratory oxidases in anaerobic systems, and are an additional indication of the flexibility of terminal oxidases, of which the distribution among anaerobic micro-organisms may be largely underestimated.
Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Ming L
ML
Wu
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Simon
S
de Vries
Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Theo A
TA
van Alen
Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Margaret K
MK
Butler
Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Huub J M
HJM
Op den Camp
Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Jan T
JT
Keltjens
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.|Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Mike S M
MSM
Jetten
Centre for Biotechnology, University of Bielefeld, Postfach 10 01 31, D-33501 Bielefeld, Germany.|Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany.|Department of Microbiology, Institute of Wetland and Water Research (IWWR), Radboud University Nijmegen, Heyendaalsweg 135, 6525 AJ Nijmegen, The Netherlands.
Marc
M
Strous
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008697:Methane / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D020133:Reverse Transcriptase Polymerase Chain Reaction
D009573:Nitrites; D009569:Nitric Oxide; D010088:Oxidoreductases; C020094:duroquinol oxidase; D008697:Methane; D010100:Oxygen