生物
激活剂(遗传学)
DNA结合蛋白
转录因子
细胞生物学
抄写(语言学)
结合位点
发起人
DNA
基因
血浆蛋白结合
遗传学
生物化学
基因表达
语言学
哲学
作者
Robert G. Martin,Judah L. Rosner
标识
DOI:10.1016/s1369-5274(00)00178-8
摘要
The AraC family of bacterial transcriptional activators regulate diverse genetic systems. Recent X-ray diffraction studies show that the monomeric MarA and Rob activators bind to their asymmetric degenerate DNA sites via two different helix-turn-helix elements. Activation by MarA, SoxS or Rob requires a particular orientation of the asymmetric binding sequence (and hence the activator), depending on its distance from the -10 RNAP signal. Genetic studies are beginning to clarify how the activators interact with RNAP. Growing evidence suggests that for the sugar metabolism activators, multiple binding sites upstream of the promoter anchor the activator in a repressing or nonactivating configuration. By interaction with the sugar and/or CRP, the activator is allosterically altered so it can bind a new set of sites that enable it to activate the promoter. Surprisingly, the virulence activator, Rns, must bind to both upstream and downstream sites in order to activate the rns promoter.
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