| Autor: |
Abdul Halim MF; Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, St. Paul, Minnesota, USA., Fonseca DR; Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, St. Paul, Minnesota, USA., Niehaus TD; Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, St. Paul, Minnesota, USA., Costa KC; Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, St. Paul, Minnesota, USA. Electronic address: kcosta@umn.edu. |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 2024 Jan; Vol. 300 (1), pp. 105550. Date of Electronic Publication: 2023 Dec 10. |
| DOI: |
10.1016/j.jbc.2023.105550 |
| Abstrakt: |
Methanogens are essential for the complete remineralization of organic matter in anoxic environments. Most cultured methanogens are hydrogenotrophic, using H 2 as an electron donor to reduce CO 2 to CH 4 , but in the absence of H 2 many can also use formate. Formate dehydrogenase (Fdh) is essential for formate oxidation, where it transfers electrons for the reduction of coenzyme F 420 or to a flavin-based electron bifurcating reaction catalyzed by heterodisulfide reductase (Hdr), the terminal reaction of methanogenesis. Furthermore, methanogens that use formate encode at least two isoforms of Fdh in their genomes, but how these different isoforms participate in methanogenesis is unknown. Using Methanococcus maripaludis, we undertook a biochemical characterization of both Fdh isoforms involved in methanogenesis. Both Fdh1 and Fdh2 interacted with Hdr to catalyze the flavin-based electron bifurcating reaction, and both reduced F 420 at similar rates. F 420 reduction preceded flavin-based electron bifurcation activity for both enzymes. In a Δfdh1 mutant background, a suppressor mutation was required for Fdh2 activity. Genome sequencing revealed that this mutation resulted in the loss of a specific molybdopterin transferase (moeA), allowing for Fdh2-dependent growth, and the metal content of the proteins suggested that isoforms are dependent on either molybdenum or tungsten for activity. These data suggest that both isoforms of Fdh are functionally redundant, but their activities in vivo may be limited by gene regulation or metal availability under different growth conditions. Together these results expand our understanding of formate oxidation and the role of Fdh in methanogenesis.
Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article.
(Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.) |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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