Structure and mechanism of helicases and nucleic acid translocases

Annu Rev Biochem. 2007;76:23-50. doi: 10.1146/annurev.biochem.76.052305.115300.


Helicases and translocases are a ubiquitous, highly diverse group of proteins that perform an extraordinary variety of functions in cells. Consequently, this review sets out to define a nomenclature for these enzymes based on current knowledge of sequence, structure, and mechanism. Using previous definitions of helicase families as a basis, we delineate six superfamilies of enzymes, with examples of crystal structures where available, and discuss these structures in the context of biochemical data to outline our present understanding of helicase and translocase activity. As a result, each superfamily is subdivided, where appropriate, on the basis of mechanistic understanding, which we hope will provide a framework for classification of new superfamily members as they are discovered and characterized.

Publication types

  • Review

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Biological Transport / physiology
  • DNA Helicases* / chemistry
  • DNA Helicases* / classification
  • DNA Helicases* / genetics
  • DNA Helicases* / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acids / chemistry
  • Nucleic Acids / metabolism
  • Peptidyl Transferases* / chemistry
  • Peptidyl Transferases* / classification
  • Peptidyl Transferases* / genetics
  • Peptidyl Transferases* / metabolism
  • Protein Conformation


  • Bacterial Proteins
  • Nucleic Acids
  • Adenosine Triphosphate
  • Peptidyl Transferases
  • DNA Helicases