Klappauf E, Schubert D
Hoppe Seylers Z Physiol Chem. 1979 Sep;360(9):1225-35. doi: 10.1515/bchm2.1979.360.2.1225.
The interaction between cholesterol and band 3-protein from human erythrocyte membranes was studied by incorporating the solubilized protein into monolayers of cholesterol and related sterols at the air-water interface and measuring the changes in surface pressure which accompanied protein incorporation. The following results were obtained: 1) Band 3-protein shows a very strong interaction with cholesterol monolayers. Both apolar and polar bonds contribute to this interaction. 2) Steroids with a structure slightly different from that of cholesterol (especially with respect to the polar group and the side chain) in most cases show a reduced affinity for band 3-protein. Thus, the protein-sterol interaction is highly specific. It is assumed that the protein-cholesterol interaction can be subidivided into two parts: an unspecific one which results from contributions from several sterol molecules, and a specific one which is due to the high affinity binding of the protein and cholesterol. The structural element responsible for the high affinity interaction is assumed to be a sterol-binding niche on the surface of band 3-protein. The sterol is thought to be held in the niche by a hydrogen bond at its polar head and a variety of hydrophobic bonds along its ring system and side chain.
通过将溶解的蛋白质掺入胆固醇和相关固醇在空气-水界面的单分子层中，并测量蛋白质掺入时伴随的表面压力变化，研究了人红细胞膜中胆固醇与带3蛋白之间的相互作用。得到以下结果：1）带3蛋白与胆固醇单分子层表现出非常强的相互作用。非极性键和极性键都对这种相互作用有贡献。2）结构与胆固醇略有不同（特别是在极性基团和侧链方面）的类固醇在大多数情况下对带3蛋白的亲和力降低。因此，蛋白质-固醇相互作用具有高度特异性。据推测，蛋白质-胆固醇相互作用可分为两部分：一部分是非特异性的，由几个固醇分子的贡献引起；另一部分是特异性的，由于蛋白质与胆固醇的高亲和力结合。负责高亲和力相互作用的结构元件被认为是带3蛋白表面的一个固醇结合位点。固醇被认为通过其极性头部的氢键以及沿其环系统和侧链的各种疏水键固定在位点中。
