2Q6N

Structure of Cytochrome P450 2B4 with Bound 1-(4-cholorophenyl)imidazole

2Q6N の概要

• エントリーDOI: 10.2210/pdb2q6n/pdb
• 関連するPDBエントリー: 1PO5 1SUO 2BDM
• 分子名称: Cytochrome P450 2B4, PROTOPORPHYRIN IX CONTAINING FE, 1-(4-CHLOROPHENYL)-1H-IMIDAZOLE (3 entities in total)
• 機能のキーワード: p450, monooxygenase, oxidoreductase, membrane protein, cyp 2b4, cyp lm2
• 由来する生物種: Oryctolagus cuniculus (rabbit)
• 細胞内の位置: Endoplasmic reticulum membrane; Peripheral membrane protein: P00178
• タンパク質・核酸の鎖数: 7
• 化学式量合計: 386683.33

構造登録者

Zhao, Y.,Sun, L.,Muralidhara, B.K.,Kumar, S.,White, M.A.,Stout, C.D.,Halpert, J.R. (登録日: 2007-06-05, 公開日: 2007-11-06, 最終更新日: 2023-08-30)

主引用文献

Zhao, Y.,Sun, L.,Muralidhara, B.K.,Kumar, S.,White, M.A.,Stout, C.D.,Halpert, J.R.
Structural and thermodynamic consequences of 1-(4-chlorophenyl)imidazole binding to cytochrome P450 2B4.
Biochemistry, 46:11559-11567, 2007

PubMed Abstract: The crystal structure of P450 2B4 bound with 1-(4-chlorophenyl)imidazole (1-CPI) has been determined to delineate the structural basis for the observed differences in binding affinity and thermodynamics relative to 4-(4-chlorophenyl)imidazole (4-CPI). Compared with the previously reported 4-CPI complex, there is a shift in the 1-CPI complex of the protein backbone in helices F and I, repositioning the side chains of Phe-206, Phe-297, and Glu-301, and leading to significant reshaping of the active site. Phe-206 and Phe-297 exchange positions, with Phe-206 becoming a ligand-contact residue, while Glu-301, rather than hydrogen bonding to the ligand, flips away from the active site and interacts with His-172. As a result the active site volume expands from 200 A3 in the 4-CPI complex to 280 A3 in the 1-CPI complex. Based on the two structures, it was predicted that a Phe-206-->Ala substitution would alter 1-CPI but not 4-CPI binding. Isothermal titration calorimetry experiments indicated that this substitution had no effect on the thermodynamic signature of 4-CPI binding to 2B4. In contrast, relative to wild-type 1-CPI binding to F206A showed significantly less favorable entropy but more favorable enthalpy. This result is consistent with loss of the aromatic side chain and possible ordering of water molecules, now able to interact with Glu-301 and exposed residues in the I-helix. Hence, thermodynamic measurements support the active site rearrangement observed in the crystal structure of the 1-CPI complex and illustrate the malleability of the active site with the fine-tuning of residue orientations and thermodynamic signatures.

PubMed: 17887776
DOI: 10.1021/bi7011614

実験手法

X-RAY DIFFRACTION (3.2 Å)