title: Solution structure of an "open" E. coli Pol III clamp loader sliding clamp complex.
abstract: Sliding clamps are opened and loaded onto primer template junctions by clamp loaders, and once loaded on DNA, confer processivity to replicative polymerases. Previously determined crystal structures of eukaryotic and T4 clamp loader-clamp complexes have captured the sliding clamps in either closed or only partially open interface conformations. In these solution structure studies, we have captured for the first time the clamp loader-sliding clamp complex from Escherichia coli using size exclusion chromatography coupled to small angle X-ray scattering (SEC-SAXS). The data suggests the sliding clamp is in an open conformation which is wide enough to permit duplex DNA binding. The data also provides information about spatial arrangement of the sliding clamp with respect to the clamp loader subunits and is compared to complex crystal structures determined from other organisms.
authors.affiliation: Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, United States.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Tondnevis
authors.affiliation: Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, MS69, Menlo Park, CA 94025, United States.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Weiss
authors.affiliation: Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, MS69, Menlo Park, CA 94025, United States.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, United States.
authors.forename: Linda B
authors.initials: LB
authors.lastname: Bloom
authors.affiliation: Biochemistry and Molecular Biology, University of Florida, PO Box 100245, Gainesville, FL 32610, United States. Electronic address: rmckenna@ufl.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: McKenna
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D002850:Chromatography, Gel; D004258:DNA Polymerase III / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D008958:Models, Molecular; D011487:Protein Conformation; D021122:Protein Subunits; D053838:Scattering, Small Angle; D012996:Solutions; D014961:X-Ray Diffraction
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D021122:Protein Subunits; D012996:Solutions; D000255:Adenosine Triphosphate; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase
keywords: AAA+ ATPase; Clamp loader; DNA replication; SAXS; Sliding clamp