title: Diffusion of nucleoside triphosphates and role of the entry site to the RNA polymerase II active center.
abstract: Nucleoside triphosphates (NTPs) diffuse to the active center of RNA polymerase II through a funnel-shaped opening that narrows to a negatively charged pore. Computer simulation shows that the funnel and pore reduce the rate of diffusion by a factor of approximately 2 x 10(-7). The resulting limitation on the rate of RNA synthesis under conditions of low NTP concentration may be overcome by NTP binding to an entry site adjacent to the active center. Binding to the entry site greatly enhances the lifetime of an NTP in the active center region, and it prevents "backtracking" and the consequent occlusion of the active site.
authors.affiliation: Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Batada
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Westover
authors.forename: David A
authors.initials: DA
authors.lastname: Bushnell
authors.forename: Michael
authors.initials: M
authors.lastname: Levitt
authors.forename: Roger D
authors.initials: RD
authors.lastname: Kornberg
mesh_terms: D001665:Binding Sites; D003198:Computer Simulation; D004058:Diffusion; D015226:Dinucleoside Phosphates / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism*; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D015226:Dinucleoside Phosphates; D012319:RNA Polymerase II