A four-helix bundle stores copper for methane oxidation.
A four-helix bundle stores copper for methane oxidation.
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DOI：
10.1038/nature14854
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发表时间：
2015-09-03
期刊：
影响因子：
64.8
通讯作者：
Dennison C
中科院分区：
文献类型：
--
作者：
Vita N;Platsaki S;Baslé A;Allen SJ;Paterson NG;Crombie AT;Murrell JC;Waldron KJ;Dennison C
甲烷氧化细菌（甲烷氧化菌）需要大量的铜来形成膜结合（颗粒）甲烷单加氧酶（pMMO）。某些甲烷氧化菌也能够切换到使用含铁的可溶性MMO（sMMO）来催化甲烷氧化，这种氧化由铜调节。MMO是自然界抑制甲烷（一种强效温室气体）大气水平的主要生物机制。此外，甲烷氧化菌和MMO在生物修复和生物转化生产散装和精细化学品以及生物能源方面具有巨大的潜力，特别是考虑到可再生能源和页岩水力压裂的甲烷可用性增加。我们已经发现并表征了一种新的铜储存蛋白（Csp 1）从甲烷氧化菌Methylosinus trichosporium OB 3b，从胞质溶胶中输出，并为pMMO储存铜。Csp 1是4-螺旋束的四聚体，每个单体以先前未见过的方式通过主要指向束核心的Cys残基结合多达13个Cu（I）离子。Csp 1是第一个在已建立的蛋白质折叠基序中储存金属的蛋白质。这项工作提供了一个详细的了解甲烷氧化菌如何积累铜的甲烷氧化。了解这一过程是必不可少的，如果要实现广泛的甲烷氧化菌生物技术应用。Csp 1的胞质同源物存在于不同的细菌中，从而挑战了这种生物体在该位置不使用铜的教条。
Methane-oxidising bacteria (methanotrophs) require large quantities of copper for the membrane-bound (particulate) methane monooxygenase (pMMO). Certain methanotrophs are also able to switch to using the iron-containing soluble MMO (sMMO) to catalyse methane oxidation, with this switchover regulated by copper. MMOs are Nature’s primary biological mechanism for suppressing atmospheric levels of methane, a potent greenhouse gas. Furthermore, methanotrophs and MMOs have enormous potential in bioremediation and for biotransformations producing bulk and fine chemicals, and in bioenergy, particularly considering increased methane availability from renewable sources and hydraulic fracturing of shale rock. We have discovered and characterised a novel copper storage protein (Csp1) from the methanotroph Methylosinus trichosporium OB3b that is exported from the cytosol, and stores copper for pMMO. Csp1 is a tetramer of 4-helix bundles with each monomer binding up to 13 Cu(I) ions in a previously unseen manner via mainly Cys residues that point into the core of the bundle. Csp1 is the first example of a protein that stores a metal within an established protein-folding motif. This work provides a detailed insight into how methanotrophs accumulate copper for the oxidation of methane. Understanding this process is essential if the wide-ranging biotechnological applications of methanotrophs are to be realised. Cytosolic homologues of Csp1 are present in diverse bacteria thus challenging the dogma that such organisms do not use copper in this location.