Crystal structure of a DExx box DNA helicase

Nature. 1996 Nov 28;384(6607):379-83. doi: 10.1038/384379a0.


There are a wide variety of helicases that unwind helical DNA and RNA substrates. The twelve helicases that have been identified in Escherichia coli play a role in almost all cellular processes involving nucleic acids. We have solved the crystal structure of a monomeric form of a DNA helicase from Bacillus stearothermophilus, alone and in a complex with ADP, at 2.5 and 2.9 A resolution, respectively. The enzyme comprises two domains with a deep cleft running between them. The ATP-binding site, which is situated at the bottom of this cleft, is formed by motifs that are conserved across the superfamily of related helicases. Unexpected structural homology with the DNA recombination protein, RecA, suggests how ATP binding and hydrolysis may drive conformational changes of the enzyme during catalysis, and implies that there is a common mechanism for all helicases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / chemistry
  • Adenosine Diphosphate / metabolism
  • Amino Acid Sequence
  • Conserved Sequence
  • Crystallography, X-Ray
  • DNA Helicases / chemistry*
  • DNA Helicases / metabolism
  • Geobacillus stearothermophilus / enzymology
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Rec A Recombinases / chemistry


  • Adenosine Diphosphate
  • Rec A Recombinases
  • DNA Helicases

Associated data

  • PDB/1PJR