颗粒态甲烷单加氧酶在甲烷营养菌中的结构与活性。
Structure and activity of particulate methane monooxygenase arrays in methanotrophs.
机构信息
Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL, USA.
出版信息
Nat Commun. 2022 Sep 5;13(1):5221. doi: 10.1038/s41467-022-32752-9.
Methane-oxidizing bacteria play a central role in greenhouse gas mitigation and have potential applications in biomanufacturing. Their primary metabolic enzyme, particulate methane monooxygenase (pMMO), is housed in copper-induced intracytoplasmic membranes (ICMs), of which the function and biogenesis are not known. We show by serial cryo-focused ion beam (cryoFIB) milling/scanning electron microscope (SEM) volume imaging and lamellae-based cellular cryo-electron tomography (cryoET) that these ICMs are derived from the inner cell membrane. The pMMO trimer, resolved by cryoET and subtomogram averaging to 4.8 Å in the ICM, forms higher-order hexagonal arrays in intact cells. Array formation correlates with increased enzymatic activity, highlighting the importance of studying the enzyme in its native environment. These findings also demonstrate the power of cryoET to structurally characterize native membrane enzymes in the cellular context.
甲烷氧化细菌在温室气体减排中发挥着核心作用，并且在生物制造方面具有潜在的应用。它们的主要代谢酶，颗粒态甲烷单加氧酶（pMMO），位于铜诱导的细胞内细胞质膜（ICM）中，其功能和生物发生尚不清楚。我们通过连续的冷冻聚焦离子束（cryoFIB）铣削/扫描电子显微镜（SEM）体积成像和基于薄片的细胞冷冻电子断层扫描（cryoET）表明，这些 ICM 源自内膜。通过 cryoET 解析的 pMMO 三聚体，并通过亚断层平均分辨率达到 ICM 中的 4.8Å，在完整细胞中形成更高阶的六方排列。排列形成与酶活性增加相关，突出了在天然环境中研究酶的重要性。这些发现还证明了 cryoET 对在细胞环境中对天然膜酶进行结构表征的强大功能。
Zotero 插件