6VK7

Crystal Structure of reduced Methylosinus trichosporium OB3b Soluble Methane Monooxygenase Hydroxylase

6VK7 の概要

• エントリーDOI: 10.2210/pdb6vk7/pdb
• 分子名称: Methane monooxygenase component A alpha chain, Methane monooxygenase, FE (III) ION, ... (5 entities in total)
• 機能のキーワード: methane monooxygenase hydroxylase, oxidoreductase
• 由来する生物種: Methylosinus trichosporium OB3b; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 124882.72

構造登録者

Jones, J.C.,Banerjee, R.,Shi, K.,Aihara, H.,Lipscomb, J.D. (登録日: 2020-01-18, 公開日: 2020-08-05, 最終更新日: 2023-10-11)

主引用文献

Jones, J.C.,Banerjee, R.,Shi, K.,Aihara, H.,Lipscomb, J.D.
Structural Studies of theMethylosinus trichosporiumOB3b Soluble Methane Monooxygenase Hydroxylase and Regulatory Component Complex Reveal a Transient Substrate Tunnel.
Biochemistry, 59:2946-2961, 2020

PubMed Abstract: The metalloenzyme soluble methane monooxygenase (sMMO) consists of hydroxylase (sMMOH), regulatory (MMOB), and reductase components. When sMMOH forms a complex with MMOB, the rate constants are greatly increased for the sequential access of O, protons, and CH to an oxygen-bridged diferrous metal cluster located in the buried active site. Here, we report high-resolution X-ray crystal structures of the diferric and diferrous states of both sMMOH and the sMMOH:MMOB complex using the components from OB3b. These structures are analyzed for O access routes enhanced when the complex forms. Previously reported, lower-resolution structures of the sMMOH:MMOB complex from the sMMO of Bath revealed a series of cavities through sMMOH postulated to serve as the O conduit. This potential role is evaluated in greater detail using the current structures. Additionally, a search for other potential O conduits in the OB3b sMMOH:MMOB complex revealed a narrow molecular tunnel, termed the W308-tunnel. This tunnel is sized appropriately for O and traverses the sMMOH-MMOB interface before accessing the active site. The kinetics of reaction of O with the diferrous sMMOH:MMOB complex in solution show that use of the MMOB V41R variant decreases the rate constant for O binding >25000-fold without altering the component affinity. The location of Val41 near the entrance to the W308-tunnel is consistent with the tunnel serving as the primary route for the transfer of O into the active site. Accordingly, the crystal structures show that formation of the diferrous sMMOH:MMOB complex restricts access through the chain of cavities while opening the W308-tunnel.

PubMed: 32692178
DOI: 10.1021/acs.biochem.0c00459

実験手法

X-RAY DIFFRACTION (2.12 Å)