Kumamoto A A, Miller W G, Gunsalus R P
Molecular Biology Institute, University of California, Los Angeles 90024.
Genes Dev. 1987 Aug;1(6):556-64. doi: 10.1101/gad.1.6.556.
DNase I footprinting and methylation protection studies have been used to analyze the binding of Escherichia coli Trp repressor to the trpR, aroH, and trp operators. The methylation protection assay shows that Trp repressor binds in two successive major grooves of the trpR operator, three successive major grooves of the aroH operator, and four successive major grooves of the trp operator. The simplest model that explains the difference in Trp repressor interaction at the three operators is that the aroH and trp operators are composed of multiple, helically stacked binding sites. When viewed in three dimensions, each site is positioned on a different face of the DNA, and together process up the surface of the DNA helix. Analysis of a deletion derivative of the trp operator supports this model.
脱氧核糖核酸酶I足迹法和甲基化保护研究已被用于分析大肠杆菌色氨酸阻遏物与trpR、aroH和trp操纵基因的结合。甲基化保护试验表明，色氨酸阻遏物结合在trpR操纵基因的两个连续大沟、aroH操纵基因的三个连续大沟以及trp操纵基因的四个连续大沟中。解释色氨酸阻遏物在这三个操纵基因上相互作用差异的最简单模型是，aroH和trp操纵基因由多个螺旋堆积的结合位点组成。从三维角度看，每个位点位于DNA的不同面上，并共同沿着DNA螺旋表面排列。对trp操纵基因的缺失衍生物的分析支持了这一模型。
