biostudies-literatureWeiblen CNatural Sciences and Engineering Research Council of CanadaCanada First Research Excellence FundMitacse0153325https://www.ebi.ac.uk/biostudies/studies/S-EPMC12607906biostudies-literatureUnknown16(11)Proteobacterial methanotrophs are dependent on the oxidation of methane for ATP production and assimilation of carbon into biomass. Interestingly, some types of gammaproteobacterial methanotrophs thrive in oxygen-depleted zones of lakes and other aquatic ecosystems despite their reliance on oxygen to support methane oxidation. The model gammaproteobacterial methanotroph, <i>Methylomonas denitrificans</i> FJG1, oxidizes methane coupled to nitrate reduction under hypoxia and highly upregulates its expression of bacteriohemerythrin (Bhr). Bhr is a homolog of eukaryotic hemerythrin, which is a protein associated with oxygen binding. Ten <i>bhr</i> homologs were identified in the genome of <i>M. denitrificans</i> FJG1, requiring phylogenetic and gene expression analyses to pinpoint which homolomBioDiverse bacteriohemerythrin genes of &lt;i&gt;Methylomonas denitrificans&lt;/i&gt; FJG1 provide insight into the survival and activity of methanotrophs in low oxygen ecosystems.PMC12607906FESDiscoveryBantingAccelerateWeiblen CKleiner MKits KDStein LYSauvageau DfalseDiverse bacteriohemerythrin genes of &lt;i&gt;Methylomonas denitrificans&lt;/i&gt; FJG1 provide insight into the survival and activity of methanotrophs in low oxygen ecosystems.Proteobacterial methanotrophs are dependent on the oxidation of methane for ATP production and assimilation of carbon into biomass. Interestingly, some types of gammaproteobacterial methanotrophs thrive in oxygen-depleted zones of lakes and other aquatic ecosystems despite their reliance on oxygen to support methane oxidation. The model gammaproteobacterial methanotroph, <i>Methylomonas denitrificans</i> FJG1, oxidizes methane coupled to nitrate reduction under hypoxia and highly upregulates its expression of bacteriohemerythrin (Bhr). Bhr is a homolog of eukaryotic hemerythrin, which is a protein associated with oxygen binding. Ten <i>bhr</i> homologs were identified in the genome of <i>M. denitrificans</i> FJG1, requiring phylogenetic and gene expression analyses to pinpoint which homolo2025-01-01T00:00:00Z2025 Nov2026-07-15T06:38:20.298Z2026-07-02T03:08:42.944ZS-EPMC126079064099622010.1128/mbio.01533-25