7b1s

Publication Abstract from PubMed

Ethane, the second most abundant hydrocarbon gas in the seafloor, is efficiently oxidized by anaerobic archaea in syntrophy with sulfate-reducing bacteria. Here, we report the 0.99-angstrom-resolution structure of the proposed ethane-activating enzyme and describe the specific traits that distinguish it from methane-generating and -consuming methyl-coenzyme M reductases. The widened catalytic chamber, harboring a dimethylated nickel-containing F(430) cofactor, would adapt the chemistry of methyl-coenzyme M reductases for a two-carbon substrate. A sulfur from methionine replaces the oxygen from a canonical glutamine as the nickel lower-axial ligand, a feature conserved in thermophilic ethanotrophs. Specific loop extensions, a four-helix bundle dilatation, and posttranslational methylations result in the formation of a 33-angstrom-long hydrophobic tunnel, which guides the ethane to the buried active site as confirmed with xenon pressurization experiments.

Crystal structure of a key enzyme for anaerobic ethane activation.,Hahn CJ, Lemaire ON, Kahnt J, Engilberge S, Wegener G, Wagner T Science. 2021 Jul 2;373(6550):118-121. doi: 10.1126/science.abg1765. PMID:34210888^[1]

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