1GEB

X-RAY CRYSTAL STRUCTURE AND CATALYTIC PROPERTIES OF THR252ILE MUTANT OF CYTOCHROME P450CAM

1GEB の概要

• エントリーDOI: 10.2210/pdb1geb/pdb
• 分子名称: CYTOCHROME P450-CAM, PROTOPORPHYRIN IX CONTAINING FE, CAMPHOR, ... (4 entities in total)
• 機能のキーワード: cytochrome p450cam, monooxygenase, electron transport
• 由来する生物種: Pseudomonas putida
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 47500.85

構造登録者

Hishiki, T.,Shimada, H.,Nagano, S.,Park, S.-Y.,Ishimura, Y. (登録日: 2000-11-01, 公開日: 2000-11-15, 最終更新日: 2023-10-25)

主引用文献

Hishiki, T.,Shimada, H.,Nagano, S.,Egawa, T.,Kanamori, Y.,Makino, R.,Park, S.Y.,Adachi, S.,Shiro, Y.,Ishimura, Y.
X-ray crystal structure and catalytic properties of Thr252Ile mutant of cytochrome P450cam: roles of Thr252 and water in the active center.
J.Biochem., 128:965-974, 2000

PubMed Abstract: The structure-function relationship in cytochrome P450cam monooxygenase was studied by employing its active site mutant Thr252Ile. X-ray crystallographic analyses of the ferric d-camphor-bound form of the mutant revealed that the mutation caused a structural change in the active site giving an enlarged oxygen-binding pocket that did not contain any hydrophilic group such as the OH group of Thr and H(2)O. The enzyme showed a low monooxygenase activity of ca. 1/10 of the activity of the wild-type enzyme. Kinetic analyses of each catalytic step revealed that the rate of proton-coupled reduction of the oxygenated intermediate of the enzyme, a ternary complex of dioxygen and d-camphor with the ferrous enzyme, decreased to about 1/30 of that of the wild-type enzyme, while the rates of other catalytic steps including the reduction of the ferric d-camphor-bound form by reduced putidaredoxin did not change significantly. These results indicated that a hydrophilic group(s) such as water and/or hydroxyl group in the active site is prerequisite to a proton supply for the reduction of the oxygenated intermediate, thereby giving support for the operation of a proton transfer network composed of Thr252, Asp251, and two other amino acids and water proposed by previous investigators.

PubMed: 11098139
DOI: 10.1093/oxfordjournals.jbchem.a022848

実験手法

X-RAY DIFFRACTION (2.03 Å)