Crystal structure of a key enzyme for anaerobic ethane activation

doi:10.1126/science.abg1765

GSTDTAP > 气候变化

DOI	10.1126/science.abg1765
	Crystal structure of a key enzyme for anaerobic ethane activation
	Cedric J. Hahn; Olivier N. Lemaire; Jörg Kahnt; Sylvain Engilberge; Gunter Wegener; Tristan Wagner
	2021-07-02
发表期刊	Science
出版年	2021
英文摘要	When released from ocean floor seeps, small hydrocarbons are rapidly consumed by micro-organisms. Methane is highly abundant and is both produced and consumed by microbes through well understood biochemical pathways. Less well understood is how ethane, also a major natural component of gaseous hydrocarbons, is metabolized. To understand how microbes take advantage of this energy and carbon source, Hahn et al. solved the x-ray crystal structures of an enzyme they call ethyl coenzyme-M reductase, which converts ethane into the thioether ethyl-coenzyme M as the entry point for catabolism. They found an expanded active site and, using a xenon gas derivatization experiment, a distinctive tunnel through the protein that is proposed to permit access of the gaseous substrate. Science , abg1765, this issue p. [118][1] 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 F430 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. [1]: /lookup/doi/10.1126/science.abg1765
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/334190
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Cedric J. Hahn,Olivier N. Lemaire,Jörg Kahnt,et al. Crystal structure of a key enzyme for anaerobic ethane activation[J]. Science,2021.
APA	Cedric J. Hahn,Olivier N. Lemaire,Jörg Kahnt,Sylvain Engilberge,Gunter Wegener,&Tristan Wagner.(2021).Crystal structure of a key enzyme for anaerobic ethane activation.Science.
MLA	Cedric J. Hahn,et al."Crystal structure of a key enzyme for anaerobic ethane activation".Science (2021).