Patrick Cramer 1, David A. Bushnell 1, Jianhua Fu 1, Averell L. Gnatt 1, Barbara Maier-Davis 1, Nancy E. Thompson 2, Richard R. Burgess 2, Aled M. Edwards 3, Peter R. David 1, and Roger D. Kornberg 1.
1 Department of Structural Biology, Stanford University
School of Medicine, Stanford, CA 94305-5126.
2 McArdle Laboratory for Cancer Research, University
of Wisconsin, Madison, Madison, WI 53706.
3 Banting and Best Department of Medical Research, University
of Toronto, Toronto, M5G 1L6, Canada
A backbone model of a 10-subunit yeast RNA polymerase II has been derived from x-ray diffraction data extending to 3 angstroms resolution. All 10 subunits exhibit a high degree of identity with the corresponding human proteins, and 9 of the 10 subunits are conserved among the three eukaryotic RNA polymerases I, II, and III. Notable features of the model include a pair of jaws, formed by subunits Rpb 1, Rpb 5, and Rpb 9, that appear to grip DNA downstream of the active center. A clamp on the DNA nearer the active center, formed by Rpb 1, Rpb 2, and Rpb 6, may be locked in the closed position by RNA, accounting for the great stability of transcribing complexes. A pore in the protein complex beneath the active center may allow entry of substrates for polymerization and exit of the transcript during proofreading and passage through pause sites in the DNA.
Additional References:
1. "A Model of Specific De-Repression within Deoxyribonucleic Acid".
2. "Localized Strand Separations within Deoxyribonucleic Acid During Selective Transcription".
3."Nuclear RNA Species Activate DNA Transcription within Chromatin".
4. "Oncogenes as Molecular Targets within Active Chromatin".