Versatility of the carboxy-terminal domain of the α subunit of RNA polymerase in transcriptional activation:: use of the DNA contact site as a protein contact site for MarA
Versatility of the carboxy-terminal domain of the α subunit of RNA polymerase in transcriptional activation:: use of the DNA contact site as a protein contact site for MarA
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DOI：
10.1111/j.1365-2958.2004.04250.x
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发表时间：
2004-10-01
影响因子：
3.6
通讯作者：
Martin, RG
中科院分区：
文献类型：
--
作者：
Dangi, B;Gronenborn, AM;Martin, RG
转录激活子MARA与RNA聚合酶(RNAP)相互作用，激活MAR调节子的启动子。在这里，我们通过基于核磁共振的化学位移映射来识别MARA和RNAPα亚单位(α-CTD)的羧基末端结构域的相互作用表面。用α-CTD滴定MarA-DNA络合物和用MarA-DNA滴定监测α-CTD的光谱变化。突变研究和保留层析证实了作图结果。一个三元复合体的模型显示，α-CTD使用一个‘265类行列子’在远离DNA的表面与Mara接触。这不同于α-CTD与CRP或FIS激活剂的相互作用，在这种情况下，‘265决定簇’与DNA接触，而同一α-CTD分子的另一个表面与激活剂接触。这些结果揭示了α-CTD在转录激活方面的新的多功能性。
The transcriptional activator, MarA, interacts with RNA polymerase (RNAP) to activate promoters of the mar regulon. Here, we identify the interacting surfaces of MarA and of the carboxy-terminal domain of the alpha subunit of RNAP (alpha-CTD) by NMR-based chemical shift mapping. Spectral changes were monitored for a MarA-DNA complex upon titration with alpha-CTD, and for alpha-CTD upon titration with MarA-DNA. The mapping results were confirmed by mutational studies and retention chromatography. A model of the ternary complex shows that alpha-CTD uses a '265-like determinant' to contact MarA at a surface distant from the DNA. This is unlike the interaction of alpha-CTD with the CRP or Fis activators where the '265 determinant' contacts DNA while another surface of the same alpha-CTD molecule contacts the activator. These results reveal a new versatility for alpha-CTD in transcriptional activation.