Stepwise translocation of nucleic acid motors

Curr Opin Struct Biol. 2010 Feb;20(1):121-7. doi: 10.1016/ Epub 2010 Jan 12.


Recent single molecule studies have made a significant contribution to the understanding of the molecular mechanism involved in the movement of motor proteins which process DNA and RNA. Measurement of stepsize in two disparate motors, NS3 helicase and ribosome both revealed 3-bp steps, which consist of three hidden substeps. Combined with previous structural studies, NS3 is likely taking a single nucleotide step of translocation coupled to one ATP binding event and this mode may be conserved in multitude of helicases. Such a stepwise translocation movement appears to occur through main contacts with the phosphate backbone. Double stranded RNA and DNA motor, RIG-I and phi29, respectively, showed translocation on a duplex while tracking exclusively a single strand of RNA or DNA in a directional manner, 5'-3' in both cases. Spontaneous dynamics displayed by ribosome ratcheting and SSB (single stranded DNA binding protein) diffusing on DNA were rectified by interacting cofactors and proteins, EF-G and RecA, respectively.

Publication types

  • Review

MeSH terms

  • Molecular Motor Proteins / chemistry
  • Molecular Motor Proteins / metabolism*
  • Nucleic Acids / chemistry*
  • Nucleic Acids / metabolism*
  • Nucleotides / chemistry
  • Nucleotides / metabolism
  • Phosphates / chemistry
  • Phosphates / metabolism
  • Protein Conformation


  • Molecular Motor Proteins
  • Nucleic Acids
  • Nucleotides
  • Phosphates