Tihonov M M, Milyaeva O Yu, Noskov B A
Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia.
Department of Colloid Chemistry, St. Petersburg State University, Universitetsky pr. 26, 198504 St. Petersburg, Russia.
Colloids Surf B Biointerfaces. 2015 May 1;129:114-20. doi: 10.1016/j.colsurfb.2015.03.034. Epub 2015 Mar 19.
Urea and guanidine hydrochloride (GuHCl) have different influence on surface properties of lysozyme solutions. The increase of GuHCl concentration leads to noticeable changes of kinetic dependencies of the dynamic surface elasticity and ellipsometric angles while the main effect of urea reduces to a strong drop of the static surface tension. The difference between the effects of these two denaturants on the surface properties of other investigated globular proteins is significantly weaker and is mainly a consequence of a different extent of the globule unfolding in the surface layer at equal concentrations of the denaturants. The obtained results for lysozyme solutions are connected with the strongly different denaturation mechanisms under the influence of urea and GuHCl. In the former case the protein preserves its globular structure in the adsorption layer at high urea concentrations (up to 9M) but without tightly packed interior of the globule and with a dynamic tertiary structure (molten globule state). On the contrary, the increase of GuHCl concentration leads to partial destruction of the protein tertiary structure in the surface layer, although this effect is not as strong as in the case of previously studied bovine serum albumin and β-lactoglobulin.
尿素和盐酸胍（GuHCl）对溶菌酶溶液的表面性质有不同影响。GuHCl浓度的增加会导致动态表面弹性和椭偏角的动力学依赖性发生显著变化，而尿素的主要作用则是使静态表面张力大幅下降。这两种变性剂对其他所研究球状蛋白质表面性质的影响差异明显较弱，主要是由于在变性剂浓度相等时，球状蛋白在表面层展开程度不同所致。溶菌酶溶液所获得的结果与在尿素和GuHCl影响下截然不同的变性机制有关。在前一种情况下，在高尿素浓度（高达9M）时，蛋白质在吸附层中保留其球状结构，但球状蛋白内部没有紧密堆积，且具有动态三级结构（熔球状态）。相反，GuHCl浓度的增加会导致表面层中蛋白质三级结构的部分破坏，尽管这种效应不如之前研究的牛血清白蛋白和β-乳球蛋白那样强烈。
