Gilson E, Alloing G, Schmidt T, Claverys J P, Dudler R, Hofnung M
Unité de Programmation Moléculaire et Toxicologie Génétique, CNRS UA271, INSERM U163, Institut Pasteur, Paris, France.
EMBO J. 1988 Dec 1;7(12):3971-4. doi: 10.1002/j.1460-2075.1988.tb03284.x.
Gram-negative bacteria are surrounded by two membranes. In these bacteria, a class of high affinity transport systems for concentrating substrates from the medium into the cell, involves a binding protein located between the outer and inner membranes, in the periplasmic region. These 'periplasmic binding-proteins' are thought to bind the substrate in the vicinity of the inner membrane, and to transfer it to a complex of inner membrane proteins for concentration into the cytoplasm. We report evidence leading us to propose that a Gram-positive bacterium, Streptococcus pneumoniae, and a mycoplasma, Mycoplasma hyorhinis, which are surrounded by a single membrane and have therefore no periplasmic region, possess an equivalent to the high affinity periplasmic binding-protein dependent transport systems, i.e. extra-cytoplasmic binding lipoprotein dependent transport systems. The 'binding lipoproteins' would be maintained at proximity of the inner membrane by insertion of their N-terminal glyceride-cysteine into this membrane.
革兰氏阴性菌被两层膜包围。在这些细菌中，一类用于将底物从培养基浓缩到细胞内的高亲和力转运系统，涉及位于外膜和内膜之间周质区域的一种结合蛋白。这些“周质结合蛋白”被认为在内膜附近结合底物，并将其转移到内膜蛋白复合物中以便浓缩到细胞质中。我们报告的证据使我们提出，一种被单层膜包围因而没有周质区域的革兰氏阳性菌——肺炎链球菌，以及一种支原体——猪鼻支原体，拥有等同于高亲和力周质结合蛋白依赖性转运系统的系统，即胞外结合脂蛋白依赖性转运系统。“结合脂蛋白”通过将其N端甘油酯 - 半胱氨酸插入内膜而维持在内膜附近。
