Farrell D H, Mikesell P, Actis L A, Crosa J H
Department of Microbiology and Immunology, School of Medicine, Oregon Health Sciences University, Portland 97201.
Gene. 1990 Jan 31;86(1):45-51. doi: 10.1016/0378-1119(90)90112-5.
The angR locus in Vibrio anguillarum encodes a trans-acting transcriptional activator which modulates several Fe2(+)-regulated loci in the anguibactin biosynthesis gene cluster. In this paper, the complete nucleotide (nt) sequence of the angR gene and deduced amino acid (aa) sequence of the AngR protein are presented. A region upstream from the angR gene is shown to have similarity with Fe2(+)-regulated operators in Escherichia coli which bind the Fur protein. The involvement of a Fur-like regulator is supported by transcription analysis which show that angR itself is Fe2(+)-regulated. The aa sequence of the AngR protein predicts a helix-turn-helix motif which shows striking homology with prokaryotic DNA-binding proteins, particularly the lambda and P22 Cro proteins. In addition, there are two 18-nt regions, upstream from the angR gene, which show similarity with the OR1 and OR2 operators of P22 cro. These regions overlap with, respectively, the -35, -10 region and the putative Fur-binding region upstream from angR. These results suggest that AngR may be a DNA-binding protein which modulates Fe2(+)-regulated transcription and is itself Fe2(+)-regulated at the transcriptional level.
鳗弧菌中的angR基因座编码一种反式作用转录激活因子，该因子可调节鳗弧菌素生物合成基因簇中的几个铁离子（Fe2+）调控基因座。本文给出了angR基因的完整核苷酸（nt）序列以及推导的AngR蛋白氨基酸（aa）序列。angR基因上游区域显示与大肠杆菌中结合Fur蛋白的铁离子（Fe2+）调控操纵子具有相似性。转录分析支持了类Fur调节因子的参与，该分析表明angR自身受铁离子（Fe2+）调控。AngR蛋白的氨基酸序列预测有一个螺旋-转角-螺旋基序，该基序与原核生物DNA结合蛋白，特别是λ和P22 Cro蛋白具有显著同源性。此外，在angR基因上游有两个18个核苷酸的区域，与P22 cro的OR1和OR2操纵子具有相似性。这些区域分别与angR上游的-35、-10区域以及假定的Fur结合区域重叠。这些结果表明，AngR可能是一种DNA结合蛋白，可调节铁离子（Fe2+）调控的转录，并且其自身在转录水平上受铁离子（Fe2+）调控。
