Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan.
Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan.
J Inorg Biochem. 2021 Dec;225:111602. doi: 10.1016/j.jinorgbio.2021.111602. Epub 2021 Sep 15.
In this focused review, we portray the recently reported 2.5 Å cyro-EM structure of the particulate methane monooxygenase (pMMO) from M. capsulatus (Bath). The structure of the functional holo-pMMO near atomic resolution has uncovered the sites of the copper cofactors including the location of the active site in the enzyme. The three coppers seen in the original X-ray crystal structures of the enzyme are now augmented by additional coppers in the transmembrane domain as well as in the water-exposed C-terminal subdomain of the PmoB subunit. The cryo-EM structure offers the first glimpse of the catalytic machinery capable of methane oxidation with high selectivity and efficiency. The findings are entirely consistent with the biochemical and biophysical findings previously reported in the literature, including the chemistry of hydrocarbon hydroxylation, regeneration of the catalyst for multiple turnovers, and the mechanism of aborting non-productive cycles to ensure kinetic competence.
在本次重点综述中，我们描绘了最近报道的来自 M. capsulatus (Bath) 的颗粒态甲烷单加氧酶 (pMMO) 的 2.5Å 冷冻电镜结构。该功能全酶 pMMO 的近原子分辨率结构揭示了铜辅因子的结合位点，包括酶的活性位点位置。在该酶的最初 X 射线晶体结构中观察到的三个铜现在通过跨膜结构域以及 PmoB 亚基的水暴露 C 末端亚结构域中的额外铜得到增强。冷冻电镜结构提供了第一个洞察具有高选择性和效率的甲烷氧化催化机制的机会。这些发现与之前文献中报道的生化和生物物理发现完全一致，包括烃类羟化反应的化学、多次周转的催化剂再生以及确保动力学能力的非生产性循环的中止机制。
