5YL3

Crystal structure of horse heart myoglobin reconstituted with manganese porphycene in resting state at pH 8.5

5YL3 の概要

• エントリーDOI: 10.2210/pdb5yl3/pdb
• 分子名称: Myoglobin, PORPHYCENE CONTAINING MN, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: globin fold, oxygen transport, muscles, oxygen storage
• 由来する生物種: Equus caballus (Horse)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 18022.51

構造登録者

Oohora, K.,Meichin, H.,Kihira, Y.,Sugimoto, H.,Shiro, Y.,Hayashi, T. (登録日: 2017-10-17, 公開日: 2017-12-27, 最終更新日: 2023-11-22)

主引用文献

Oohora, K.,Meichin, H.,Kihira, Y.,Sugimoto, H.,Shiro, Y.,Hayashi, T.
Manganese(V) Porphycene Complex Responsible for Inert C-H Bond Hydroxylation in a Myoglobin Matrix.
J. Am. Chem. Soc., 139:18460-18463, 2017

PubMed Abstract: A mechanistic study of HO-dependent C-H bond hydroxylation by myoglobin reconstituted with a manganese porphycene was carried out. The X-ray crystal structure of the reconstituted protein obtained at 1.5 Å resolution reveals tight incorporation of the complex into the myoglobin matrix at pH 8.5, the optimized pH value for the highest turnover number of hydroxylation of ethylbenzene. The protein generates a spectroscopically detectable two-electron oxidative intermediate in a reaction with peracid, which has a half-life up to 38 s at 10 °C. Electron paramagnetic resonance spectra of the intermediate with perpendicular and parallel modes are silent, indicating formation of a low-spin Mn-oxo species. In addition, the Mn-oxo species is capable of promoting the hydroxylation of sodium 4-ethylbenzenesulfonate under single turnover conditions with an apparent second-order rate constant of 2.0 M s at 25 °C. Furthermore, the higher bond dissociation enthalpy of the substrate decreases the rate constant, in support of the proposal that the H-abstraction is one of the rate-limiting steps. The present engineered myoglobin serves as an artificial metalloenzyme for inert C-H bond activation via a high-valent metal species similar to the species employed by native monooxygenases such as cytochrome P450.

PubMed: 29237270
DOI: 10.1021/jacs.7b11288

実験手法

X-RAY DIFFRACTION (1.5 Å)