Miura K, Inouye S, Nakazawa A
Department of Biochemistry, Yamaguchi University School of Medicine, Japan.
Biochem Mol Biol Int. 1998 Dec;46(5):933-41. doi: 10.1080/15216549800204482.
The transcription of OP2 encoding enzymes for m-toluate catabolism on the Pseudomonas putida TOL plasmid is activated by basal-level XylS protein in the presence of m-toluate or by overproduced XylS protein in the absence of m-toluate. In this study, in vivo dimethyl sulfate (DMS) footprinting was performed to understand the mechanism of transcriptional regulation of OP2 promoter by XylS. In the presence of overproduced XylS without m-toluate, several protected nucleotides were observed, indicating the binding of RNA polymerase to DNA. However, the protection was canceled upon addition of m-toluate. These results suggest that RNA polymerase is retained by XylS on the OP2 promoter in the absence of inducer, and is released by m-toluate binding to XylS, concomitant with transcription.
恶臭假单胞菌TOL质粒上编码间甲苯甲酸分解代谢酶的OP2的转录，在有间甲苯甲酸存在时由基础水平的XylS蛋白激活，或在无间甲苯甲酸存在时由过量表达的XylS蛋白激活。在本研究中，进行了体内硫酸二甲酯（DMS）足迹分析，以了解XylS对OP2启动子的转录调控机制。在无间甲苯甲酸但有过量表达的XylS存在时，观察到几个受保护的核苷酸，表明RNA聚合酶与DNA结合。然而，加入间甲苯甲酸后这种保护作用消失。这些结果表明，在没有诱导剂的情况下，RNA聚合酶被XylS保留在OP2启动子上，并且随着间甲苯甲酸与XylS结合而释放，同时伴随转录。
