Rudel T, Facius D, Barten R, Scheuerpflug I, Nonnenmacher E, Meyer T F
Max-Planck-Institut für Biologie, Abteilung Infektionsbiologie, Tübingen, Germany.
Proc Natl Acad Sci U S A. 1995 Aug 15;92(17):7986-90. doi: 10.1073/pnas.92.17.7986.
The Gram-negative bacterial pathogen Neisseria gonorrhoeae is naturally competent for transformation with species-related DNA. We show here that two phase-variable pilus-associated proteins, the major pilus subunit (pilin, or PilE) and PilC, a factor known to function in the assembly and adherence of gonococcal pili, are essential for transformation competence. The PilE and PilC proteins are necessary for the conversion of linearized plasmid DNA carrying the Neisseria-specific DNA uptake signal into a DNase-resistant form. The biogenesis of typical pilus fibers is neither essential nor sufficient for this process. DNA uptake deficiency of defined piliated pilC1,2 double mutants can be complemented by expression of a cloned pilC2 gene in trans. The PilC defect can also be restored by the addition of purified PilC protein, or better, pili containing PilC protein, to the mutant gonococci. Our data suggest that the two phase-variable Pil proteins act on the bacterial cell surface and cooperate in DNA recognition and/or outer membrane translocation.
革兰氏阴性细菌病原体淋病奈瑟菌天然具有摄取与物种相关DNA并进行转化的能力。我们在此表明，两种相位可变的菌毛相关蛋白，即主要菌毛亚基（菌毛蛋白，或PilE）和PilC（一种已知在淋球菌菌毛组装和黏附中起作用的因子），对于转化能力至关重要。PilE和PilC蛋白对于将携带奈瑟菌特异性DNA摄取信号的线性化质粒DNA转化为抗DNA酶形式是必需的。典型菌毛纤维的生物合成对于此过程既非必需也不充分。特定的有菌毛的pilC1,2双突变体的DNA摄取缺陷可以通过反式表达克隆的pilC2基因来互补。通过向突变的淋球菌中添加纯化的PilC蛋白，或者更好的是含有PilC蛋白的菌毛，也可以恢复PilC缺陷。我们的数据表明，这两种相位可变的Pil蛋白作用于细菌细胞表面，并在DNA识别和/或外膜转运中协同作用。
