Kim T K, Lagrange T, Wang Y H, Griffith J D, Reinberg D, Ebright R H
Howard Hughes Medical Institute and Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12268-73. doi: 10.1073/pnas.94.23.12268.
By using site-specific protein-DNA photocrosslinking, we define the positions of TATA-binding protein, transcription factor IIB, transcription factor IIF, and subunits of RNA polymerase II (RNAPII) relative to promoter DNA within the human transcription preinitiation complex. The results indicate that the interface between the largest and second-largest subunits of RNAPII forms an extended, approximately 240 A channel that interacts with promoter DNA both upstream and downstream of the transcription start. By using electron microscopy, we show that RNAPII compacts promoter DNA by the equivalent of approximately 50 bp. Together with the published structure of RNAPII, the results indicate that RNAPII wraps DNA around its surface and suggest a specific model for the trajectory of the wrapped DNA.
通过使用位点特异性蛋白质-DNA光交联技术，我们确定了TATA结合蛋白、转录因子IIB、转录因子IIF以及RNA聚合酶II（RNAPII）亚基相对于人类转录起始前复合物中启动子DNA的位置。结果表明，RNAPII最大亚基和第二大亚基之间的界面形成了一个延伸的、约240埃的通道，该通道与转录起始位点上下游的启动子DNA相互作用。通过电子显微镜，我们发现RNAPII将启动子DNA压缩了相当于约50个碱基对的长度。结合已发表的RNAPII结构，这些结果表明RNAPII将DNA缠绕在其表面，并提出了一个关于缠绕DNA轨迹的特定模型。
