Filloux A, Bally M, Ball G, Akrim M, Tommassen J, Lazdunski A
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
EMBO J. 1990 Dec;9(13):4323-9. doi: 10.1002/j.1460-2075.1990.tb07881.x.
The xcp genes are required for protein secretion by Pseudomonas aeruginosa. They are involved in the second step of the process, i.e. the translocation across the outer membrane, after the exoproteins have reached the periplasm in a signal peptide dependent fashion. The nucleotide sequence of a 2.5 kb DNA fragment containing xcp genes showed at least two complete open reading frames, potentially encoding proteins with molecular weights of 41 and 19 kd. Products with these apparent molecular weights were identified after expression of the DNA fragment in vitro and in vivo. Subcloning and complementation experiments showed that both proteins are required for secretion. The two products are located in the inner membrane and share highly significant homologies with the PulL and PulM proteins which are required for the specific secretion of pullulanase in Klebsiella pneumoniae. These homologies reveal the existence of a common mechanism for protein secretion in Pseudomonas aeruginosa and Klebsiella pneumoniae.
xcp基因是铜绿假单胞菌分泌蛋白质所必需的。它们参与该过程的第二步，即在胞外蛋白以信号肽依赖的方式到达周质后，跨外膜转运。包含xcp基因的一个2.5 kb DNA片段的核苷酸序列显示至少有两个完整的开放阅读框，可能编码分子量分别为41 kd和19 kd的蛋白质。在该DNA片段于体外和体内表达后，鉴定出了具有这些表观分子量的产物。亚克隆和互补实验表明这两种蛋白质对于分泌都是必需的。这两种产物位于内膜中，并且与肺炎克雷伯菌中支链淀粉酶特异性分泌所必需的PulL和PulM蛋白具有高度显著的同源性。这些同源性揭示了铜绿假单胞菌和肺炎克雷伯菌中蛋白质分泌存在共同机制。
