Major domain swiveling revealed by the crystal structures of complexes of E. coli Rep helicase bound to single-stranded DNA and ADP

Cell. 1997 Aug 22;90(4):635-47. doi: 10.1016/s0092-8674(00)80525-5.


Crystal structures of binary and ternary complexes of the E. coli Rep helicase bound to single-stranded (ss) DNA or ssDNA and ADP were determined to a resolution of 3.0 A and 3.2 A, respectively. The asymmetric unit in the crystals contains two Rep monomers differing from each other by a large reorientation of one of the domains, corresponding to a swiveling of 130 degrees about a hinge region. Such domain movements are sufficiently large to suggest that these may be coupled to translocation of the Rep dimer along DNA. The ssDNA binding site involves the helicase motifs Ia, III, and V, whereas the ADP binding site involves helicase motifs I and IV. Residues in motifs II and VI may function to transduce the allosteric effects of nucleotides on DNA binding. These structures represent the first view of a DNA helicase bound to DNA.

Publication types

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

MeSH terms

  • Adenosine Diphosphate / metabolism*
  • Adenosine Triphosphatases / metabolism*
  • Amino Acid Sequence
  • Binding Sites
  • Crystallography, X-Ray
  • DNA Helicases*
  • DNA, Single-Stranded / metabolism*
  • Escherichia coli / enzymology
  • Escherichia coli Proteins
  • Macromolecular Substances
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Sequence Alignment


  • DNA, Single-Stranded
  • Escherichia coli Proteins
  • Macromolecular Substances
  • rep protein, E coli
  • Adenosine Diphosphate
  • Adenosine Triphosphatases
  • DNA Helicases