4MGJ

Crystal structure of cytochrome P450 2B4 F429H in complex with 4-CPI

4MGJ の概要

• エントリーDOI: 10.2210/pdb4mgj/pdb
• 関連するPDBエントリー: 4MGL 4MGO
• 分子名称: Cytochrome P450 2B4, PROTOPORPHYRIN IX CONTAINING FE, 4-(4-CHLOROPHENYL)IMIDAZOLE, ... (4 entities in total)
• 機能のキーワード: p450 fold, closed conformation, 4-cpi binding, oxidoreductase
• 由来する生物種: Oryctolagus cuniculus (European rabbit,Japanese white rabbit,domestic rabbit,rabbits)
• 細胞内の位置: Endoplasmic reticulum membrane; Peripheral membrane protein: P00178
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 54965.19

構造登録者

Yang, Y.,Zhang, H.,Usharani, D.,Bu, W.,Im, S.,Tarasev, M.,Rwere, F.,Meagher, J.,Sun, C.,Stuckey, J.,Shaik, S.,Waskell, L. (登録日: 2013-08-28, 公開日: 2014-08-13, 最終更新日: 2024-02-28)

主引用文献

Yang, Y.,Zhang, H.,Usharani, D.,Bu, W.,Im, S.,Tarasev, M.,Rwere, F.,Pearl, N.M.,Meagher, J.,Sun, C.,Stuckey, J.,Shaik, S.,Waskell, L.
Structural and Functional Characterization of a Cytochrome P450 2B4 F429H Mutant with an Axial Thiolate-Histidine Hydrogen Bond.
Biochemistry, 53:5080-5091, 2014

PubMed Abstract: The structural basis of the regulation of microsomal cytochrome P450 (P450) activity was investigated by mutating the highly conserved heme binding motif residue, Phe429, on the proximal side of cytochrome P450 2B4 to a histidine. Spectroscopic, pre-steady-state and steady-state kinetic, thermodynamic, theoretical, and structural studies of the mutant demonstrate that formation of an H-bond between His429 and the unbonded electron pair of the Cys436 axial thiolate significantly alters the properties of the enzyme. The mutant lost >90% of its activity; its redox potential was increased by 87 mV, and the half-life of the oxyferrous mutant was increased ∼37-fold. Single-crystal electronic absorption and resonance Raman spectroscopy demonstrated that the mutant was reduced by a small dose of X-ray photons. The structure revealed that the δN atom of His429 forms an H-bond with the axial Cys436 thiolate whereas the εN atom forms an H-bond with the solvent and the side chain of Gln357. The amide of Gly438 forms the only other H-bond to the tetrahedral thiolate. Theoretical quantification of the histidine-thiolate interaction demonstrates a significant electron withdrawing effect on the heme iron. Comparisons of structures of class I-IV P450s demonstrate that either a phenylalanine or tryptophan is often found at the location corresponding to Phe429. Depending on the structure of the distal pocket heme, the residue at this location may or may not regulate the thermodynamic properties of the P450. Regardless, this residue appears to protect the thiolate from solvent, oxidation, protonations, and other deleterious reactions.

PubMed: 25029089
DOI: 10.1021/bi5003794

実験手法

X-RAY DIFFRACTION (2.41 Å)