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1geb
From Proteopedia
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'''X-RAY CRYSTAL STRUCTURE AND CATALYTIC PROPERTIES OF THR252ILE MUTANT OF CYTOCHROME P450CAM''' | '''X-RAY CRYSTAL STRUCTURE AND CATALYTIC PROPERTIES OF THR252ILE MUTANT OF CYTOCHROME P450CAM''' | ||
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[[Category: Park, S Y.]] | [[Category: Park, S Y.]] | ||
[[Category: Shimada, H.]] | [[Category: Shimada, H.]] | ||
| - | [[Category: | + | [[Category: Cytochrome p450cam]] |
| - | [[Category: | + | [[Category: Monooxygenase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:27:56 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:27, 2 May 2008
X-RAY CRYSTAL STRUCTURE AND CATALYTIC PROPERTIES OF THR252ILE MUTANT OF CYTOCHROME P450CAM
Overview
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.
About this Structure
1GEB is a Single protein structure of sequence from Pseudomonas putida. Full crystallographic information is available from OCA.
Reference
X-ray crystal structure and catalytic properties of Thr252Ile mutant of cytochrome P450cam: roles of Thr252 and water in the active center., Hishiki T, Shimada H, Nagano S, Egawa T, Kanamori Y, Makino R, Park SY, Adachi S, Shiro Y, Ishimura Y, J Biochem. 2000 Dec;128(6):965-74. PMID:11098139 Page seeded by OCA on Fri May 2 17:27:56 2008
