Wilson M J, Lamont I L
Department of Biochemistry, University of Otago, Dunedin, New Zealand.
Biochem Biophys Res Commun. 2000 Jul 5;273(2):578-83. doi: 10.1006/bbrc.2000.2996.
The PvdS protein is essential for synthesis of the siderophore pyoverdine by Pseudomonas aeruginosa. PvdS has some sequence similarity to a family of alternative sigma factor proteins (the ECF [extracytoplasmic factor] family) that direct bacterial RNA polymerases to transcribe genes encoding extracytoplasmic factors. PvdS was purified as a His-tagged protein (hPvdS) and this was used to test the hypothesis that PvdS is a sigma factor protein. The purified protein caused core RNA polymerase from Escherichia coli to bind specifically to the promoters of pyoverdine synthesis genes and enabled transcription from these promoters in vitro. In addition, PvdS was found to co-purify with RNA polymerase from P. aeruginosa, indicating that PvdS associates with RNA polymerase inside the bacteria. These results show that PvdS is a sigma factor protein.
PvdS蛋白对于铜绿假单胞菌合成铁载体绿脓菌素至关重要。PvdS与一类替代sigma因子蛋白（胞外因子[ECF]家族）具有一定的序列相似性，这类蛋白可引导细菌RNA聚合酶转录编码胞外因子的基因。PvdS被纯化成为带His标签的蛋白（hPvdS），并用于验证PvdS是一种sigma因子蛋白的假说。纯化后的蛋白使来自大肠杆菌的核心RNA聚合酶特异性结合到绿脓菌素合成基因的启动子上，并能在体外实现这些启动子的转录。此外，还发现PvdS可与铜绿假单胞菌的RNA聚合酶共同纯化，这表明PvdS在细菌内部与RNA聚合酶相关联。这些结果表明PvdS是一种sigma因子蛋白。
