2026-09-16 マックス・プランク研究所
Bogs sequester greenhouse gases. That is why many drained bogs have been restored to their natural state. However, research shows that methane emissions may initially rise sharply. © Max Planck Institute for Terrestrial Microbiology/Geisel
＜関連情報＞
- https://www.mpg.de/26978299/a-new-tool-for-investigating-microbial-methane-production-in-natural-environments
- https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cbic.70535
イソシアニドを化学ツールとして用いた[Fe]-水素化酵素依存性メタン生成の同定 Isocyanides as a Chemical Tool for Identifying [Fe]-Hydrogenase-Dependent Methanogenesis
Shunsuke Nomura, Seigo Shima
ChemBioChem Published: 14 September 2026
DOI:https://doi.org/10.1002/cbic.70535
Abstract
In the hydrogenotrophic methanogens cultivated under nickel-sufficient standard medium (~5 µM Ni2+), two cytosolic [NiFe]-hydrogenases, F420-reducing hydrogenase (Frh) and heterodisulfide reductase (Hdr)-associating hydrogenase (Mvh), mainly provide electrons to the methanogenic pathway. In Methanothermobacter marburgensis under strictly nickel-limited conditions (< 50 nM Ni2+), which are encountered in certain natural environments, Frh and Mvh are strongly downregulated. Under these conditions, a coupled reaction with [Fe]-hydrogenase (Hmd) and F420-dependent methylene-tetrahydromethanopterin dehydrogenase (Mtd) substitutes for the function of Frh, where F420-dependent electron-donating protein (Elp) complexes with Hdr and donates electrons from the reduced form of F420 to Hdr. Thus, Hmd mainly provides electrons to methanogenesis in nickel-limited environments. In this study, to evaluate the potential of isocyanides as an Hmd-specific chemical tool to probe this pathway, we determined their inhibitory effects on the H2-dependent F420-reducing activity in the cell extract and on the in vitro methanogenesis reaction in a cell extract and in a cell suspension. Isocyanides specifically inhibited the activities of the samples from nickel-limited cells. The inhibitory effect on the cell suspension was strengthened by the use of a hydrophobic isocyanide. These results demonstrate their potential as a chemical tool for identifying in situ Hmd-dependent methanogenesis activity in natural environmental samples.
