van Klompenburg W, Nilsson I, von Heijne G, de Kruijff B
Department of Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands.
EMBO J. 1997 Jul 16;16(14):4261-6. doi: 10.1093/emboj/16.14.4261.
The orientation of many membrane proteins is determined by the asymmetric distribution of positively charged amino acid residues in cytoplasmic and translocated loops. The positive-inside rule states that loops with large amounts of these residues tend to have cytoplasmic locations. Orientations of constructs derived from the inner membrane protein leader peptidase from Escherichia coli were found to depend on the anionic phospholipid content of the membrane. Lowering the contents of anionic phospholipids facilitated membrane passage of positively charged loops. On the other hand, elevated contents of acidic phospholipids in the membrane rendered translocation more sensitive to positively charged residues. The results demonstrate that anionic lipids are determinants of membrane protein topology and suggest that interactions between negatively charged phospholipids and positively charged amino acid residues contribute to the orientation of membrane proteins.
许多膜蛋白的取向由细胞质环和转运环中带正电荷氨基酸残基的不对称分布决定。正内规则表明，含有大量这些残基的环往往位于细胞质中。发现源自大肠杆菌内膜蛋白前导肽酶的构建体的取向取决于膜中阴离子磷脂的含量。降低阴离子磷脂的含量有助于带正电荷的环通过膜。另一方面，膜中酸性磷脂含量的升高使转运对带正电荷的残基更敏感。结果表明，阴离子脂质是膜蛋白拓扑结构的决定因素，并表明带负电荷的磷脂与带正电荷的氨基酸残基之间的相互作用有助于膜蛋白的取向。
