Fakultät Chemie, TU Dortmund University, D-44221 Dortmund, Germany.
Langmuir. 2013 Jun 25;29(25):8025-30. doi: 10.1021/la401296f. Epub 2013 Jun 11.
There seems to be a general relation between the standard Gibbs energy change of unfolding, ΔG°unf, of a protein and its affinity to aqueous-solid interfaces. So-called "hard" proteins (ΔG°unf is large) are found to adsorb less strongly to such interfaces than "soft" proteins (ΔG°unf is small). Here, we provide direct support for this rule by using high pressure to modulate the folding stability of a protein. We have performed high-pressure total internal reflection fluorescence (HP-TIRF) spectroscopy and high-pressure neutron reflectometry (HP-NR) to measure the degree of adsorption and the structure of lysozyme on planar solid surfaces as a function of pressure for the first time. By carrying out these experiments at hydrophilic and hydrophobic surfaces with varying concentrations of glycerol, we have found strong evidence that ΔG°unf has indeed a direct influence. At high pressures, there is a larger degree of lysozyme adsorption, probably because lysozyme becomes a "soft" protein under these conditions. The results of this study demonstrate that high pressure is a very useful tool to explore thermodynamics of protein-interface interactions.
似乎蛋白质的去折叠标准吉布斯自由能变化（ΔG°unf）与其对水-固界面的亲和力之间存在普遍关系。所谓的“硬”蛋白质（ΔG°unf 较大）比“软”蛋白质（ΔG°unf 较小）对这种界面的吸附力较弱。在这里，我们通过使用高压来调节蛋白质的折叠稳定性，为这一规则提供了直接支持。我们首次进行了高压全内反射荧光（HP-TIRF）光谱和高压中子反射（HP-NR）测量，以测量溶菌酶在平面固体表面上的吸附程度和结构随压力的变化。通过在具有不同甘油浓度的亲水性和疏水性表面上进行这些实验，我们有强有力的证据表明 ΔG°unf 确实有直接影响。在高压下，溶菌酶的吸附程度更大，可能是因为溶菌酶在这些条件下变成了“软”蛋白质。这项研究的结果表明，高压是探索蛋白质-界面相互作用热力学的非常有用的工具。
