NMR Studies of Lysozyme Surface Accessibility by Using Different Paramagnetic Relaxation Probes
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- 作者：Andrea Bernini ; Ottavia Spiga ; Vincenzo Venditti ; Filippo Prischi ; Luisa Bracci ; Angela Pui-Ling Tong ; Wing-Tak Wong ; and Neri Niccolai
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：July 26, 2006
- 年：2006
- 卷：128
- 期：29
- 页码：9290 - 9291
- 全文大小：103K
- 年卷期：v.128,no.29(July 26, 2006)
- ISSN：1520-5126
文摘
Paramagnetic probes, whose approach to proteins can be monitored by nuclear magnetic resonance (NMR) studies, have been found to be of primary relevance for investigating protein surfaces' accessibility. Here, a Gd(III) neutral complex which contains two metal ions, [Gd2(L7)(H2O)2], is suggested as a paramagnetic probe particularly suited for systematic NMR investigation of protein surface accessibility, due to an expected high relaxivity and to the lack of electric charge which could favor specific interactions. Hen egg white lysozyme has been used as a model system to verify the absence of preferential approaches of this paramagnetic probe to specific protein moieties by comparing paramagnetic perturbation profiles of 1H-13C HSQC signals obtained in the presence of TEMPOL and [Gd2(L7)(H2O)2]. From the similarity of the measured paramagnetic perturbation profiles induced by the two different probes, specific interactions of [Gd2(L7)(H2O)2] with the enzyme could be ruled out. The large size of the latter probe is suggested to be responsible for the strong paramagnetic perturbations observed for C
H groups which are located in convex surface-exposed regions. The combined use of the two probes reveals fine details of the dynamics controlling their approach toward the protein surface.
H groups which are located in convex surface-exposed regions. The combined use of the two probes reveals fine details of the dynamics controlling their approach toward the protein surface.