铜和其他重金属离子诱导大肠杆菌抗铜启动子的研究

通过测定荧光酶活性研究了大肠杆菌抗铜基因上的两个铜诱导的启动子。结果表明，在缺少抗铜质粒ｐＢＩＮ１９ｐｃｏ的情况下，启动子ＰｐｃｏＡｂｏｘ－ｌｕｘ和ＰｐｃｏＡｌｏｎｇ－ｌｕｘ的最大诱导均出现在５ｍｍｏｌ／ＬＣｕＳＯ４，而且ＰｐｃｏＡｂｏｘ是一个比即ＰｐｃｏＡｌｏｎｇ强的启动子；铜对两个ＰｐｃｏＥ－ｌｕｘ构建的诱导的生物荧光曲线中，有两个峰，第一个峰出现在０．５ｍｍｏｌ／ＬＣｕＳＯ４时，第二个峰亦即最大诱导出现在约５ｍｍｏｌ／ＬＣｕＳＯ４时，并且ＰｐｃｏＥｌｏｎｇ的活性比ＰｐｃｏＥｂｏｘ高。结果还表明，启动子ＰｐｃｏＥ比ＰｐｃｏＡ活性高得多；此外，由于两个Ｐｐｃｏｓｈｏｒｔ－ｌｕｘ构建均不显示任何荧光酶活性，说明Ｃｏｐｐｅｒｂｏｘ对于抗铜基因来说是非常重要甚至是必需的。在质粒ｐＢＩＮ１９ｐｃｏ存在的情况下，所有启动子的最大诱导均出现在６ｍｍｏｌ／ＬＣｕＳＯ４时，而且比无该质粒时的相应最大诱导值高得多。以其他重金属离子进行诱导实验结果表明，锌和镍可以作为诱导物且锌的效果较好，镉和银则不能诱导抗铜系统。

Study on the Induction of pco Promoters from Escherichia coli with Copper and Other Metal Ions

Two copper inducible promoters in the pco determinant of Escherichia coli were studied by determining the luciferase activity of report vector pUCD615 The results showed that in teh absence of pBIN19 pco ,providing copper resistance genes in trans, the maximum induction for both P pcoA lux fusions was observed at 5mmol/L CuSO 4 and P pcoA box was a stronger promoter than P pcoA long. There were two peaks in the bioluminesecnecs of both P pcoE-lux fusions induced with increasing copper concentration, the first peak was observed at about 0.5mmol/L CuSO 4,the second peak,also the maximuminduction,was obsrved at about 5mmol/L CuSO 4,and P pcoE long was a stronger promoter than P pcoE box. The results indicated that the P pcoE promoter was a much stronger promoter than P pcoA promoter. The results also showed that the copper box was very inportant and essential to pco promoters, since both of the P pco short- lux fusions failed to show any luciferase activity when they were induced with copper. In the presence of pBIN19 pco , the maximum inductions of all of the P pco - lux fragments were observed at 6mmol/L CuSO 4 and they were much higher than those observed in the absence of pBIN19 pco , and the results also indicated that the cells were able to resistant to much higher copper concentration in the presence of pBIN19 pco than in the absence of that. Zn 2 and Ni 2 could be inducers for all of the fragments and Zn 2 was a better inducer than Ni 2 , and Cd 2 and Ag did not induce the pco system