Evidence for an Induced-Fit Mechanism Operating in Pi Class Glutathione Transferases

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• 作者：Aaron J. Oakley ; Mario Lo Bello ; Giorgio Ricci ; Giorgio Federici ; and Michael W. Parker
• 刊名：Biochemistry
• 出版年：1998
• 出版时间：July 14, 1998
• 年：1998
• 卷：37
• 期：28
• 页码：9912 - 9917
• 全文大小：153K
• 年卷期：v.37,no.28(July 14, 1998)
• ISSN：1520-4995

文摘

Three-dimensional structures of the apo form of human pi class glutathione transferase havebeen determined by X-ray crystallography. The structures suggest the enzyme recognizes its substrate,glutathione, by an induced-fit mechanism. Compared to complexed forms of the enzyme, the environmentaround the catalytic residue, Tyr 7, remains unchanged in the apoenzyme. This observation supports theview that Tyr 7 does not act as a general base in the reaction mechanism. The observed cooperativity ofthe dimeric enzyme may be due to the movements of a helix that forms one wall of the active site and,in particular, to movements of a tyrosine residue that is located in the subunit interface.