Exchange of Xcp (Gsp) secretion machineries between Pseudomonas aeruginosa and Pseudomonas alcaligenes:: Species specificity unrelated to substrate recognition
Exchange of Xcp (Gsp) secretion machineries between Pseudomonas aeruginosa and Pseudomonas alcaligenes:: Species specificity unrelated to substrate recognition
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DOI：
10.1128/jb.183.3.959-967.2001
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发表时间：
2001-02-01
影响因子：
3.2
通讯作者：
Filloux, A
中科院分区：
文献类型：
--
作者：
De Groot, A;Koster, M;Filloux, A
铜绿假单胞菌和产碱假单胞菌是革兰氏阴性菌，它们通过II型或一般分泌途径分泌蛋白质，这需要至少12个XCP基因产物(XcpA和XcpP to-Z)，尽管这一分泌途径非常保守，但革兰氏阴性菌通常不能分泌其他物种的外源蛋白。根据对Erwinia获得的结果，已经提出XcpP和/或XcpQ同源物决定这种分泌特异性(M.Linderberg，G.P.Salmond，和A.Collmer，MEL。微生物。20：175-190,1996)。在本研究中，我们报道产碱假单胞菌的XcpP和XcpQ不能替代它们各自的铜绿假单胞菌。然而，这些互补失败与物种对外源蛋白的特异性识别无关，因为这些细菌可以相互分泌外源蛋白。此外，当产碱假单胞菌xcpP和xcpQ在铜绿假单胞菌xcpPQ缺失突变体中同时表达时，可以观察到互补，尽管只在琼脂平板上而不是在液体培养中。在液体培养中生长后，未检测到耐热产碱杆菌XcpQ多聚体，而单体清晰可见。综上所述，我们的结果表明，一个功能性的XCP机制的组装需要XcpP和XcpQ之间以及XcpP或XcpQ与另一个尚未表征的成分(S)之间的物种特异性相互作用。
Pseudomonas aeruginosa and Pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type II or general secretory pathway, which requires at least 12 xcp gene products (XcpA and XcpP to -Z), Despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. Based on results obtained with Erwinia, it has been proposed that the XcpP and/or XcpQ homologs determine this secretion specificity (M. Linderberg, G. P. Salmond, and A. Collmer, Mel. Microbiol. 20:175-190, 1996). In the present study, we report that XcpP and XcpQ of P. alcaligenes could not substitute for their respective P. aeruginosa counterparts. However, these complementation failures could not be correlated to species specific recognition of exoproteins, since these bacteria could secrete exoproteins of each other. Moreover, when P. alcaligenes xcpP and xcpQ were expressed simultaneously in a P. aeruginosa xcpPQ deletion mutant, complementation was observed, albeit only on agar plates and not in liquid cultures. After growth in liquid culture the heat-stable P. alcaligenes XcpQ multimers were not detected, whereas monomers were clearly visible. Together, our results indicate that the assembly of a functional Xcp machinery requires species-specific interactions between XcpP and XcpQ and between XcpP or XcpQ and another, as yet uncharacterized component(s).