NMR studies on the surface accessibility of the archaeal protein Sso7d by using TEMPOL and Gd(III)(DTPA-BMA) as paramagnetic probes

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• 作者：Andrea Bernini ; Vincenzo Venditti ; Ottavia Spiga ; Arianna Ciutti ; Filippo Prischi ; Roberto Consonni ; Lucia Zetta ; Ivana Arosio ; Paola Fusi ; Annamaria Guagliardi ; Neri Niccolai
• 关键词：Surface accessibility ; Protein NMR ; Paramagnetic probes ; TEMPOL ; Gd(III)(DTPA-BMA)
• 刊名：Biophysical Chemistry
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：137
• 期：2-3
• 页码：71-75
• 全文大小：385 K

文摘

Understanding how proteins are approached by surrounding molecules is fundamental to increase our knowledge of life at atomic resolution. Here, the surface accessibility of a multifunctional small protein, the archaeal protein Sso7d from Sulfolobus solfataricus, has been investigated by using TEMPOL and Gd(III)(DTPA-BMA) as paramagnetic probes. The DNA binding domain of Sso7d appears very accessible both to TEMPOL and Gd(III)(DTPA-BMA). Differences in paramagnetic attenuation profiles of ¹H–¹⁵N HSQC protein backbone amide correlations, observed in the presence of the latter paramagnetic probes, are consistent with the hydrogen bond acceptor capability of the N-oxyl moiety of TEMPOL to surface exposed Sso7d amide groups. By using the gadolinium complex as a paramagnetic probe a better agreement between Sso7d structural features and attenuation profile is achieved. It is interesting to note that the protein P-loop region, in spite of the high surface exposure predicted by the available protein structures, is not approached by TEMPOL and only partially by Gd(III)(DTPA-BMA).