The first reaction of the methanogenic pathway from carbon dioxide (CO) is the reduction and condensation of CO to formyl-methanofuran, catalyzed by formyl-methanofuran dehydrogenase (Fmd). Strongly ...The first reaction of the methanogenic pathway from carbon dioxide (CO) is the reduction and condensation of CO to formyl-methanofuran, catalyzed by formyl-methanofuran dehydrogenase (Fmd). Strongly reducing electrons for this reaction are generated by heterodisulfide reductase (Hdr) in complex with hydrogenase or formate dehydrogenase (Fdh) using a flavin-based electron-bifurcation mechanism. Here, we report enzymological and structural characterizations of Fdh-Hdr-Fmd complexes from . The complexes catalyze this reaction using electrons from formate and the reduced form of the electron carrier F. Conformational changes in HdrA mediate electron bifurcation, and polyferredoxin FmdF directly transfers electrons to the CO reduction site, as evidenced by methanofuran-dependent flavin-based electron bifurcation even without free ferredoxin, a diffusible electron carrier between Hdr and Fmd. Conservation of Hdr and Fmd structures suggests that this complex is common among hydrogenotrophic methanogens.
EMDB-12196: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, conformational state 1, focused refinement of mobile arm and Hdr core 手法: EM (単粒子) / 解像度: 3.3 Å
EMDB-12197: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase complex from Methanospirillum hungatei, dimeric complex, focused refinement of conformational state 1 of the mobile arm 手法: EM (単粒子) / 解像度: 3.2 Å
EMDB-12198: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, focused refinement of conformational state 2 of the mobile arm 手法: EM (単粒子) / 解像度: 3.1 Å
EMDB-12199: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, conformational state 2, focused refinement of the mobile arm and Hdr core 手法: EM (単粒子) / 解像度: 3.1 Å
EMDB-12200: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, FdhA subunit by focussed classification and focussed refinement 手法: EM (単粒子) / 解像度: 3.6 Å
EMDB-12201: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, focussed refinement of the FmdABCDG subcomplex 手法: EM (単粒子) / 解像度: 3.3 Å
EMDB-12202: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, hexameric complex, D3-symmetry refined 手法: EM (単粒子) / 解像度: 4.4 Å
EMDB-12203: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, dimeric complex, focussed refinement of the FmdF2 region 手法: EM (単粒子) / 解像度: 3.8 Å
EMDB-12204: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, hexameric complex, focussed refinement of the Fmd region 手法: EM (単粒子) / 解像度: 3.4 Å
EMDB-12205: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanispirillum hungatei, hexameric complex, focussed refinement of Hdr core 手法: EM (単粒子) / 解像度: 3.4 Å
EMDB-12206, PDB-7bkb: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase complex from Methanospirillum hungatei (hexameric, composite structure) 手法: EM (単粒子) / 解像度: 3.5 Å
EMDB-12207: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, hexameric complex, focussed refinement of conformational state 1 of the mobile arm 手法: EM (単粒子) / 解像度: 3.1 Å
EMDB-12208: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase from Methanospirillum hungatei, hexameric complex, focussed refinement of conformational state 2 of the mobile arm 手法: EM (単粒子) / 解像度: 4.0 Å
EMDB-12210, PDB-7bkd: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase complex from Methanospirillum hungatei (heterodislfide reductase core and mobile arm in conformational state 1, composite structure) 手法: EM (単粒子) / 解像度: 3.0 Å
EMDB-12211: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase complex from Methanospirillum hungatei, dimeric complex, focused refinement of HdrA2B2C2 core 手法: EM (単粒子) / 解像度: 2.58 Å
EMDB-12212, PDB-7bke: Formate dehydrogenase - heterodisulfide reductase - formylmethanofuran dehydrogenase complex from Methanospirillum hungatei (heterodisulfide reductase core and mobile arm in conformational state 2, composite structure) 手法: EM (単粒子) / 解像度: 2.8 Å