Co-localization of particulate methane monooxygenase and cd1 nitrite reductase in the denitrifying methanotroph 'Candidatus Methylomirabilis oxyfera'.
'Candidatus Methylomirabilis oxyfera'; is a polygon-shaped bacterium that was shown to have the unique ability to couple anaerobic methane oxidation to denitrification, through a newly discovered intra-aerobic pathway. Recently, the complete genome of Methylomirabilis oxyfera was assembled into a 2.7-Mb circular single chromosome by metagenomic sequencing. The genome of M. oxyfera revealed the full potential to perform both methane oxidation and the conversion of nitrite via nitric oxide into oxygen and dinitrogen gas. In this study, we show by immunogold localization that key enzymes from both methane- and nitrite-converting pathways are indeed present in single M. oxyfera cells. Antisera targeting the particulate methane monooxygenase (pMMO) and the cd(1) nitrite reductase (NirS) were raised and used for immunogold localization in both single- and double-labelling experiments. Our previous studies have shown that M. oxyfera does not develop pMMO-containing intracytoplasmic membranes as is observed in classical proteobacterial methanotrophs. Our results suggest that in M. oxyfera, the pMMO and NirS enzymes localized to the cytoplasmic membrane and periplasm, respectively. Further, double-labelling showed co-occurrence of pMMO and NirS in single M. oxyfera cells.
Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, The Netherlands.
Ming L
ML
Wu
Theo A
TA
van Alen
Elly G
EG
van Donselaar
Marc
M
Strous
Mike S M
MS
Jetten
Laura
L
van Niftrik
D000693:Anaerobiosis; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D058440:Denitrification; D008697:Methane / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics / Q000378:metabolism*; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport
D001426:Bacterial Proteins; D010105:Oxygenases; C021555:methane monooxygenase; D009572:Nitrite Reductases; D008697:Methane