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NMR Studies of Lysozyme Surface Accessibility by Using Different Paramagnetic Relaxation Probes
Journal of the American Chemical Society (2006)
  • Andrea Bernini, University of Siena
  • Ottavia Spiga, University of Siena
  • Vincenzo Venditti, University of Siena
  • Filippo Prischi, University of Siena
  • Luisa Bracci, University of Siena
  • Angela Pui-Ling Tong, The University of Hong Kong
  • Wing-Tak Wong
  • Neri Niccolai, University of Siena

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 CαH 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.

Publication Date
Publisher Statement
Reprinted (adapted) with permission from J. Am. Chem. Soc., 2006, 128 2006 American Chemical Society.
Citation Information
Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, et al.. "NMR Studies of Lysozyme Surface Accessibility by Using Different Paramagnetic Relaxation Probes" Journal of the American Chemical Society Vol. 128 Iss. 29 (2006)
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