Yeast RNA polymerase II at 5 A resolution.
Appropriate treatment of X-ray diffraction from an unoriented 18-heavy atom cluster derivative of a yeast RNA polymerase II crystal gave significant phase information to 5 A resolution. The validity of the phases was shown by close similarity of a 6 A electron density map to a 16 A molecular envelope of the polymerase from electron crystallography. Comparison of the 6 A X-ray map with results of electron crystallography of a paused transcription elongation complex suggests functional roles for two mobile protein domains: the tip of a flexible arm forms a downstream DNA clamp; and a hinged domain may serve as an RNA clamp, enclosing the transcript from about 8-18 residues upstream of the 3'-end in a tunnel.
Fu
J
J
Department of Structural Biology, Stanford University School of Medicine, Fairchild Science Center, California 94305, USA.
Gnatt
A L
AL
Bushnell
D A
DA
Jensen
G J
GJ
Thompson
N E
NE
Burgess
R R
RR
David
P R
PR
Kornberg
R D
RD
D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism; D008854:Microscopy, Electron; D008958:Models, Molecular; D009038:Motion; D011487:Protein Conformation; D012313:RNA / Q000378:metabolism; D012319:RNA Polymerase II / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D017356:Synchrotrons
D012313:RNA; D004247:DNA; D012319:RNA Polymerase II