The metal centers of particulate methane monooxygenase from Methylosinus trichosporium OB3b
The metal centers of particulate methane monooxygenase from Methylosinus trichosporium OB3b
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DOI：
10.1021/bi800598h
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发表时间：
2008-07-01
期刊：
影响因子：
2.9
通讯作者：
Rosenzweig, Amy C.
中科院分区：
文献类型：
--
作者：
Hakemian, Amanda S.;Kondapalli, Kalyan C.;Rosenzweig, Amy C.
颗粒甲烷单加氧酶（pMMO）是一种膜结合的金属酶，在甲烷氧化细菌中将甲烷氧化为甲醇。pMMO活性位点的性质和总金属含量是有争议的，光谱学和晶体学数据表明存在单核铜中心、双核铜中心、三核中心和二铁中心或其组合。大多数研究集中在来自荚膜甲基球菌（Bath）的pMMO。来自第二种生物体，发孢甲基弯菌OB 3b的pMMO已经通过光谱和晶体学方法纯化和表征。纯化的M.丝孢霉OB 3b pMMO含有类似于2个铜离子/100 kDa原聚体。电子顺磁共振（EPR）光谱参数表明，2型铜（II）是作为两个不同的物种。扩展的X射线吸收精细结构（EXAFS）的数据是最适合与氧/氮配体，并揭示了在2.52埃的铜-铜相互作用。相应地，M.发孢霉OB 3b pMMO显示双核铜中心，与观察到的类似。以前在M的晶体结构中。capsulatus（Bath）pMMO.然而，两种生物体的pMMO结构之间存在显著差异。单核铜中心存在于M。capsulatus（Bath）pMMO在M. trichosporium OB 3b pMMO的金属中心被锌占据，而M. capsulatus（Bath）的pMMO结构被M中的铜占据。发孢霉OB3b pMMO。这些发现扩展了以前的工作pMMO从M。capsulatus（巴斯），并提供了新的见解不同的金属中心的功能的重要性。
Particulate methane monooxygenase (pMMO) is a membrane-bound metalloenzyme that oxidizes methane to methanol in methanotrophic bacteria. The nature of the pMMO active site and the overall metal content are controversial, with spectroscopic and crystallographic data suggesting the presence of a mononuclear copper center, a dinuclear copper center, a trinuclear center, and a diiron center or combinations, thereof. Most studies have focused on pMMO from Methylococcus capsulatus (Bath). pMMO from a second organism, Methylosinus trichosporium OB3b, has been purified and characterized, by spectroscopic and crystallograpic methods. Purified M. trichosporium OB3b pMMO contains similar to 2 copper ions per 100 kDa protomer. Electron paramagnetic resonance (EPR) spectroscopic parameters indicate that type 2 Cu(II) is present as two distinct species. Extended X-ray absorption fine structure (EXAFS) data are best fit with oxygen/nitrogen ligands and reveal a Cu-Cu interaction at 2.52 angstrom. Correspondingly, X-ray crystallography of M. trichosporium OB3b pMMO shows a dinuclear copper center, similar to that observed. previously in the crystal structure of M. capsulatus (Bath) pMMO. There are, however, significant differences between the pMMO structures from the two organisms. A mononuclear copper center present in M. capsulatus (Bath) pMMO is absent in M. trichosporium OB3b pMMO, whereas a metal center occupied by zinc in the M. capsulatus (Bath) pMMO structure is occupied by copper in M. trichosporium. OB3b pMMO. These findings extend previous work on pMMO from M. capsulatus (Bath) and provide new insight into the functional importance of the different metal centers.