Multi-heme cytochrome-mediated extracellular electron transfer by the anaerobic methanotroph 'Candidatus Methanoperedens nitroreducens'.
Xueqin ZhangGeorgina H JoyceAndy O LeuJing ZhaoHesamoddin RabieeBernardino VirdisGene W TysonZhiguo YuanSimon Jon McIlroyShihu HuPublished in: Nature communications (2023)
Anaerobic methanotrophic archaea (ANME) carry out anaerobic oxidation of methane, thus playing a crucial role in the methane cycle. Previous genomic evidence indicates that multi-heme c-type cytochromes (MHCs) may facilitate the extracellular electron transfer (EET) from ANME to different electron sinks. Here, we provide experimental evidence supporting cytochrome-mediated EET for the reduction of metals and electrodes by 'Candidatus Methanoperedens nitroreducens', an ANME acclimated to nitrate reduction. Ferrous iron-targeted fluorescent assays, metatranscriptomics, and single-cell imaging suggest that 'Ca. M. nitroreducens' uses surface-localized redox-active cytochromes for metal reduction. Electrochemical and Raman spectroscopic analyses also support the involvement of c-type cytochrome-mediated EET for electrode reduction. Furthermore, several genes encoding menaquinone cytochrome type-c oxidoreductases and extracellular MHCs are differentially expressed when different electron acceptors are used.
Keyphrases
- electron transfer
- microbial community
- wastewater treatment
- single cell
- sewage sludge
- anaerobic digestion
- nitric oxide
- high throughput
- high resolution
- cancer therapy
- gene expression
- genome wide
- quantum dots
- risk assessment
- carbon dioxide
- drug delivery
- mass spectrometry
- human health
- molecular dynamics simulations
- reduced graphene oxide
- heavy metals
- health risk
- raman spectroscopy
- protein kinase