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Publication Abstract from PubMed

In methanogenic archaea, the carbon dioxide (CO2) fixation and methane-forming steps are linked through the heterodisulfide reductase (HdrABC)-[NiFe]-hydrogenase (MvhAGD) complex that uses flavin-based electron bifurcation to reduce ferredoxin and the heterodisulfide of coenzymes M and B. Here, we present the structure of the native heterododecameric HdrABC-MvhAGD complex at 2.15-angstrom resolution. HdrB contains two noncubane [4Fe-4S] clusters composed of fused [3Fe-4S]-[2Fe-2S] units sharing 1 iron (Fe) and 1 sulfur (S), which were coordinated at the CCG motifs. Soaking experiments showed that the heterodisulfide is clamped between the two noncubane [4Fe-4S] clusters and homolytically cleaved, forming coenzyme M and B bound to each iron. Coenzymes are consecutively released upon one-by-one electron transfer. The HdrABC-MvhAGD atomic model serves as a structural template for numerous HdrABC homologs involved in diverse microbial metabolic pathways.

Methanogenic heterodisulfide reductase (HdrABC-MvhAGD) uses two noncubane [4Fe-4S] clusters for reduction.,Wagner T, Koch J, Ermler U, Shima S Science. 2017 Aug 18;357(6352):699-703. doi: 10.1126/science.aan0425. PMID:28818947^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.