Solution Structure of Glutathione Bound to Human Glutathione Transferase P1-1: Comparison of NMR Measurements with the Crystal Structure

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• 作者：Maria Nicotra ; Maurizio Paci ; Marco Sette ; Aaron J. Oakley ; Michael W. Parker ; Mario Lo Bello ; Anna Maria Caccuri ; Giorgio Federici ; and Giorgio Ricci
• 刊名：Biochemistry
• 出版年：1998
• 出版时间：March 3, 1998
• 年：1998
• 卷：37
• 期：9
• 页码：3020 - 3027
• 全文大小：83K
• 年卷期：v.37,no.9(March 3, 1998)
• ISSN：1520-4995

文摘

The conformation of the bound glutathione (GSH) in the active siteof the human glutathionetransferase P1-1 (EC 2.5.1.18) has been studied by transferred NOEmeasurements and compared withthose obtained by X-ray diffraction data. Two-dimensional TRNOESYand TRROESY experiments havebeen performed under fast-exchange conditions. The family of GSHconformers, compatible with TRNOEdistance constraints, shows a backbone structure very similar to thecrystal model. Interesting differenceshave been found in the side chain regions. After restrained energyminimization of a representative NMRconformer in the active site, the sulfur atom is not found inhydrogen-bonding distance of the hydroxylgroup of Tyr 7. This situation is similar to the one observed inan "atypical" crystal complex grown atlow pH and low temperature. The NMR conformers display also apoorly defined structure of the glutamylmoiety, and the presence of an unexpected intermolecular NOE couldindicate a different interaction ofthis substrate portion with the G-site. The NMR data seem toprovide a snapshot of GSH in a precomplexwhere the GSH glutamyl end is bound in a different fashion. Theexistence of this precomplex is supportedby pre-steady-state kinetic experiments [Caccuri, A. M., Lo Bello, M.,Nuccetelli, M., Nicotra, M., Rossi,P., Antonini, G., Federici, G., and Ricci, G. (1998) Biochemistry37, 3028-3034] and preliminary time-resolved fluorescence data.