THE C-TERMINAL REGION OF THE VIBRIO-FISCHERI LUXR PROTEIN CONTAINS AN INDUCER-INDEPENDENT LUX GENE ACTIVATING DOMAIN
THE C-TERMINAL REGION OF THE VIBRIO-FISCHERI LUXR PROTEIN CONTAINS AN INDUCER-INDEPENDENT LUX GENE ACTIVATING DOMAIN
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DOI：
10.1073/pnas.88.24.11115
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发表时间：
1991-12-01
影响因子：
11.1
通讯作者：
GREENBERG, EP
中科院分区：
文献类型：
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作者：
CHOI, SH;GREENBERG, EP
费氏弧菌发光基因被自诱导物和250个氨基酸残基的LuxR蛋白激活。为了开发LuxR结构和功能的一般观点，产生了一组luxR 5 '缺失突变。研究了编码活性LuxR蛋白的10个luxR突变质粒，所述活性LuxR蛋白具有范围从残基2-5（DELTA-2-5）至残基2-182（DELTA-2-182）的缺失。截短的LuxR蛋白对发光基因的转录激活程度为野生型水平的0.01%至> 200%。具有小缺失（高达DELTA-2-20）的LuxR蛋白具有活性并且保持自诱导物依赖性，具有残基2-58和2-138之间的缺失的LuxR蛋白显示低活性并且不受自诱导物影响，并且具有大缺失的LuxR蛋白如DELTA-2-162蛋白具有高活性并且不依赖于自诱导物。然而，缺失等于或大于DELTA-2-20的蛋白质不能自动调节luxR。我们的数据表明，有一个C-末端LuxR结构域能够作为一个转录激活因子。我们认为，N-末端区域的LuxR残基20和58之间开始，并延伸到该区域的残基138-162掩蔽的C-末端结构域的激活功能。位置20之前的残基是自动调节功能所需的。显示野生型luxR在编码DELTA-2-58至DELTA-2-138蛋白的luxR基因上占优势的实验表明N-末端臂掩蔽了luxDNA结合。
The Vibrio fischeri luminescence genes are activated by an autoinducer and the 250-amino acid residue LuxR protein. To develop a general view of LuxR structure and function, a set of luxR 5'-deletion mutations was generated. Ten luxR mutant plasmids encoding active LuxR proteins with deletions ranging from residues 2-5 (DELTA-2-5) to residues 2-182 (DELTA-2-182) were studied. The degree of transcriptional activation of luminescence genes by the truncated LuxR proteins ranged from 0.01% to > 200% of the wild-type level. LuxR proteins with small deletions (up to DELTA-2-20) were active and remained autoinducer-dependent, LuxR proteins with deletions between residues 2-58 and 2-138 showed low activity and were not affected by autoinducer, and LuxR proteins with large deletions such as the DELTA-2-162 protein were highly active and autoinducer-independent. However, proteins with deletions equal to or greater than DELTA-2-20 were unable to autoregulate luxR. Our data indicate there is a C-terminal LuxR domain capable of functioning as a transcriptional activator. We suggest that an N-terminal region of LuxR starting between residues 20 and 58 and extending to the region of residues 138-162 masks the activator function of the C-terminal domain. Residues prior to position 20 are needed for autoregulatory function. Experiments showing that wild-type luxR is dominant over luxR genes coding the DELTA-2-58 through DELTA-2-138 proteins indicate the N-terminal arm masks lux DNA binding.