On the Hofmeister Effect: Fluctuations at the Protein鈥揥ater Interface and the Surface Tension

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• 作者：Ferenc Bog谩r ; Ferenc Bartha ; Zolt谩n N谩sztor ; L谩szl贸 F谩bi谩n ; Bal谩zs Leitgeb ; Andr谩s D茅r
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：July 24, 2014
• 年：2014
• 卷：118
• 期：29
• 页码：8496-8504
• 全文大小：398K
• ISSN：1520-5207

文摘

We performed molecular dynamics simulations on the tryptophane-cage miniprotein using a nonpolarizable force field, in order to model the effect of concentrated water solutions of neutral salts on protein conformation, which is a manifestation of Hofmeister effects. From the equilibrium values and the fluctuations of the solvent accessible surface area of the miniprotein, the salt-induced changes of the mean value of protein鈥搘ater interfacial tension were determined. At 300 K, the chaotropic ClO₄^{鈥?/sup> and NO₃鈥?/sup> decreased the interfacial tension according to their position in the Hofmeister series (by approximately 5 and 2.7 mN/m, respectively), while the kosmotropic F鈥?/sup> increased it (by 1 mN/m). These values were compared to those obtained from the Gibbs equation using the excess surface adsorption calculated from the probability distribution of the water molecules and ions around the miniprotein, and the two sets were found to be very close to each other. Our results present a direct evidence for the central role of interfacial tension and fluctuations at the protein鈥搘ater interface in Hofmeister phenomena, and provide a computational method for the determination of the protein鈥搘ater interfacial tension, establishing a link between the phenomenological and microscopic description of protein鈥搘ater interfaces.}