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[摘要]：Bacterial promoters are recognized by RNA polymerase (RNAP) sigma subunit, which specifically interacts with the -10 and -35 promoter elements. Here, we provide evidence that the beta' zipper, an evolutionarily conserved loop of the largest subunit of RNAP core, interacts with promoter spacer, a DNA segment that separates the -10 and -35 promoter elements, and facilitates the formation of stable closed promoter complex. Depending on the spacer sequence, the proposed interaction of the beta' zipper with the spacer can also facilitate open promoter complex formation and even substitute for interactions of the sigma subunit with the -35 element. These results suggest that there exists a novel class of promoters that rely on interaction of the beta' zipper with promoter spacer, along with or instead of interactions of sigma subunit with the -35 element, for their activity. Finally, our data suggest that sequence-dependent interactions of the beta' zipper with DNA can contribute to promoter-proximal sigma-dependent RNAP pausing, a recently recognized important step of transcription control. The EMBO Journal (2011) 30, 3766-3775. doi: 10.1038/ emboj. 2011.252; Published online 26 July 2011 |
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