Nakano Shunji, Nakano Michiko M, Zhang Ying, Leelakriangsak Montira, Zuber Peter
Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97006, USA.
Proc Natl Acad Sci U S A. 2003 Apr 1;100(7):4233-8. doi: 10.1073/pnas.0637648100. Epub 2003 Mar 17.
Transcriptional activator proteins in bacteria often operate by interaction with the C-terminal domain of the alpha-subunit of RNA polymerase (RNAP). Here we report the discovery of an "anti-alpha" factor Spx in Bacillus subtilis that blocks transcriptional activation by binding to the alpha-C-terminal domain, thereby interfering with the capacity of RNAP to respond to certain activator proteins. Spx disrupts complex formation between the activator proteins ResD and ComA and promoter-bound RNAP, and it does so by direct interaction with the alpha-subunit. ResD- and ComA-stimulated transcription requires the proteolytic elimination of Spx by the ATP-dependent protease ClpXP. Spx represents a class of transcriptional regulators that inhibit activator-stimulated transcription by interaction with alpha.
细菌中的转录激活蛋白通常通过与RNA聚合酶(RNAP)α亚基的C末端结构域相互作用来发挥作用。在此,我们报告了在枯草芽孢杆菌中发现一种“抗α”因子Spx,它通过与α-末端结构域结合来阻断转录激活,从而干扰RNAP对某些激活蛋白作出反应的能力。Spx破坏了激活蛋白ResD和ComA与启动子结合的RNAP之间的复合物形成,并且它是通过与α亚基直接相互作用来实现的。ResD和ComA刺激的转录需要ATP依赖性蛋白酶ClpXP对Spx进行蛋白水解消除。Spx代表了一类通过与α相互作用来抑制激活剂刺激转录的转录调节因子。