title: Three-dimensional structure of yeast RNA polymerase II at 16 A resolution.
abstract: The structure of yeast RNA polymerase II has been determined by three-dimensional reconstruction from electron micrographs of two-dimensional crystals at approximately 16 A resolution. The most prominent feature of the structure is an arm of protein density surrounding a channel about 25 A in diameter, similar to that found previously for E. coli RNA polymerase. The 25 A-diameter channel bifurcates on one face of the protein, connecting with a 25 A-wide groove and with a channel about half as wide. The 25 A channel and groove, and the narrow channel, may bind double- and single-stranded nucleic acids, respectively. A finger of protein density projecting from the molecule adjacent to the arm-like feature may represent the C-terminal domain of the largest subunit. These results provide a structural basis for analyses of the transcription process and its regulation.
authors.affiliation: Beckman Laboratories for Structural Biology, Department of Cell Biology, Stanford University, California 94305.
authors.forename: S A
authors.initials: SA
authors.lastname: Darst
authors.forename: A M
authors.initials: AM
authors.lastname: Edwards
authors.forename: E W
authors.initials: EW
authors.lastname: Kubalek
authors.forename: R D
authors.initials: RD
authors.lastname: Kornberg
mesh_terms: D008854:Microscopy, Electron / Q000379:methods; D008958:Models, Molecular; D008961:Models, Structural; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000648:ultrastructure*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
chemical_list: D012319:RNA Polymerase II