Crystal structure of the processivity clamp loader gamma (gamma) complex of E. coli DNA polymerase III

Cell. 2001 Aug 24;106(4):429-41. doi: 10.1016/s0092-8674(01)00463-9.


The gamma complex, an AAA+ ATPase, is the bacterial homolog of eukaryotic replication factor C (RFC) that loads the sliding clamp (beta, homologous to PCNA) onto DNA. The 2.7/3.0 A crystal structure of gamma complex reveals a pentameric arrangement of subunits, with stoichiometry delta':gamma(3):delta. The C-terminal domains of the subunits form a circular collar that supports an asymmetric arrangement of the N-terminal ATP binding domains of the gamma motor and the structurally related domains of the delta' stator and the delta wrench. The structure suggests a mechanism by which the gamma complex switches between a closed state, in which the beta-interacting element of delta is hidden by delta', and an open form similar to the crystal structure, in which delta is free to bind to beta.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding Sites
  • Crystallography, X-Ray
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase / chemistry*
  • DNA-Directed DNA Polymerase / metabolism
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Macromolecular Substances
  • Models, Molecular
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary


  • Macromolecular Substances
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase

Associated data

  • PDB/1JR3