title: The clamp-loading complex for processive DNA replication.
abstract: DNA polymerase requires two processing factors, sliding clamps and clamp loaders, to direct rapid and accurate duplication of genomic DNA. In eukaryotes, proliferating cell nuclear antigen (PCNA), the ring-shaped sliding clamp, encircles double-stranded DNA within its central hole and tethers the DNA polymerases onto DNA. Replication factor C (RFC) acts as the clamp loader, which correctly installs the sliding clamp onto DNA strands in an ATP-dependent manner. Here we report the three-dimensional structure of an archaeal clamp-loading complex (RFC-PCNA-DNA) determined by single-particle EM. The three-dimensional structure of the complex, reconstituted in vitro using a nonhydrolyzable ATP analog, reveals two components, a closed ring and a horseshoe-shaped element, which correspond to PCNA and RFC, respectively. The atomic structure of PCNA fits well into the closed ring, suggesting that this ternary complex represents a state just after the PCNA ring has closed to encircle the DNA duplex.
authors.affiliation: Department of Structural Biology, Biomolecular Engineering Research Institute, Suita, Osaka 565-0874, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Miyata
authors.forename: Takuji
authors.initials: T
authors.lastname: Oyama
authors.forename: Kouta
authors.initials: K
authors.lastname: Mayanagi
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ishino
authors.forename: Yoshizumi
authors.initials: Y
authors.lastname: Ishino
authors.forename: Kosuke
authors.initials: K
authors.lastname: Morikawa
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D017931:DNA Primers; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006868:Hydrolysis; D008854:Microscopy, Electron
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D000255:Adenosine Triphosphate; D004247:DNA