生物膜结构研究的一些进展

膜蛋白三维结构的解析存在很多困难.最近几年由于一些通道(如K⁺通道，Cl^-通道，水通道Aquaporin 1等)和泵（如Ca^2＋泵）的结晶获得成功，这些膜蛋白具有原子分辨率三维结构的解析才得以完成，从而基本阐明一些极性分子和离子选择性通过生物膜的分子机理.在膜脂结构方面，动物细胞质膜膜脂的分布是不均匀的.近年来已多方面证明，质膜具有一些被命名为“脂筏（lipid rafts）”和“质膜微囊（Caveolae）”的微区.它们富含鞘脂和胆固醇。简单介绍了这些脂质微区的大小、组分以及动态变化.根据研究结果，这类脂质微区含有大量信号分子，很可能具有信号传递中心的作用.此外，对脂筏在膜运送过程中的作用也进行一些评述.

Recent Advances in The Study of Membrane Structure

The task of determining the structure of membrane proteins has been hindered by experimental difficulties. Recent success in crystallising a number of channels (K⁺ channel, Cl^- channel, Aquaporin 1 etc) and pumps (Ca²⁺ pumps) has led to the determination of 3D structures of a number of proteins responsible for selective transport of polar molecules and ions across biological membranes.In recent years several lines of evidence indicate that the lipids in the plasma membrane of animal cells are inhomogeneously distributed. Lipid rafts and caveolae are cholesterol-sphingolipid enriched microdomains. The characteristics of these domains, such as size, composition and dynamics were briefly reviewed in the present paper. A large number of signalling molecules are concentrated within these lipid microdomains, which has been proposed to function as signaling centers. Besides, the roles of lipid rafts in membrane transport were also discussed.