Purification and characterization of the OmpR protein, a positive regulator involved in osmoregulatory expression of the ompF and ompC genes in Escherichia coli.
Purification and characterization of the OmpR protein, a positive regulator involved in osmoregulatory expression of the ompF and ompC genes in Escherichia coli.
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OmpR 蛋白的纯化和表征，OmpR 蛋白是参与大肠杆菌中 ompF 和 ompC 基因渗透调节表达的正调节因子。
DOI：
10.1016/s0021-9258(18)66860-7
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
S. Mizushima
中科院分区：
文献类型：
--
作者：
Y. Jo;F. Nara;S. Ichihara;T. Mizuno;S. Mizushima
The OmpR protein is a positive regulator involved in osmoregulatory expression of the ompF and ompC genes, which respectively code for major outer membrane proteins OmpF and OmpC of Escherichia coli. The OmpR protein has been purified to homogeneity from an overproducing strain harboring an ompR gene-carrying plasmid. Throughout the purification the OmpR protein behaved as a single entity. The molecular weight determined on sodium dodecyl sulfate-polyacrylamide gel, the total amino acid composition, and the NH2-terminal amino acid sequence of the purified protein were essentially the same as those deduced from the nucleotide sequence of the ompR gene. Molecular weight determination and cross-linking study on the native protein revealed that the purified protein exists as a monomer. The purified OmpR protein was specifically bound to the promoter regions of the ompC and ompF genes. Experiments with a series of upstream deletions of the ompC and ompF promoters revealed that the region upstream from the -35 region was indispensable for OmpR binding to both the ompC and the ompF promoters. Although it has been proposed that depending on the medium osmolarity the OmpR protein may exist in two alternative structures, which respectively regulate functioning of the ompC and the ompF promoters, the purified OmpR protein appeared to be homogeneous and interacted with both promoters to the same extent.
