Unusual Plastoquinones in Non‐Phototrophic Nitrifying Bacteria
Isoprenoid quinones are important compounds in most organisms. They are essential in electron and proton transport in respiratory and photosynthetic electron transport chains, and additional functions include oxidative stress defence. The biologically most relevant quinones are naphthoquinones including menaquinone and benzoquinones including ubiquinone and plastoquinone. They differ in their polar headgroup structures, physicochemical properties, and distribution among organisms. Menaquinone is the most widespread quinone in prokaryotes, ubiquinone occurs only in bacteria of the phylum Pseudomonadota and eukaryotes, and plastoquinone exists in phototrophic Cyanobacteria and plants. We found that chemolithoautotrophic nitrifying bacteria of the genus Nitrospira (phylum Nitrospirota) exclusively possess unusual methyl-plastoquinones with a standard redox potential below that of canonical plastoquinone and ubiquinone but above menaquinone, suggesting functional roles in reverse electron transport, ammonia oxidation, alternative energy metabolisms, and oxidative stress mitigation. This extends the known diversity of quinones and suggests that plastoquinone derivatives are essential in ecologically important, non-phototrophic bacteria.
Authors
- Jaap S. Sinninghe Damsté (ORCID: https://orcid.org/0000-0002-8683-1854)
- Michael Wagner (ORCID: https://orcid.org/0000-0002-9778-7684)
- Hiroshi Shiigi (ORCID: https://orcid.org/0000-0002-1664-7816)
- Johanna Palmetzhofer (ORCID: https://orcid.org/0000-0002-0573-0892)
- Holger Daims (ORCID: https://orcid.org/0000-0002-4195-0913)
- Nicole J. Bale (ORCID: https://orcid.org/0000-0001-9118-3890)
- Hikaru Ikeda (ORCID: https://orcid.org/0000-0002-2327-2207)
- Michel Koenen (ORCID: https://orcid.org/0000-0002-8398-6500)
- Petra Pjevac (ORCID: https://orcid.org/0000-0001-7344-302X)
- Christopher J. Sedlacek (ORCID: https://orcid.org/0000-0002-6002-4982)
- Hayk Palabikyan (ORCID: https://orcid.org/0000-0002-8046-7318)
- Satohiro Itagaki
- Yojiro Yamamoto
- Hayato Fujimura
Institutions
- University of Southern Indiana (US)
- University of Vienna (AT)
- Osaka Prefecture University (JP)
- Utrecht University (NL)
- Royal Netherlands Institute for Sea Research (NL)
- Osaka International University (JP)
- Tokyo Metropolitan University (JP)
- Aalborg University (DK)
Publication Details
- Journal
- Environmental Microbiology Reports
- Published
- 2025-08-01
- DOI
- https://doi.org/10.1111/1758-2229.70174
- Citations
- 2
- Primary Topic
- Wastewater Treatment and Nitrogen Removal
- Type
- article
- Field-Weighted Citation Impact
- 1.01
Funders
- Soehngen Institute of Anaerobic Microbiology
- European Commission
- Austrian Science Fund
- Universität Wien
- European Research Council
- Japan Society for the Promotion of Science