Stepwise translocation of nucleic acid motors

Sua Myong, Taekjip Ha

Research output: Contribution to journalReview articlepeer-review


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 φ{symbol}29, 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.

Original languageEnglish (US)
Pages (from-to)121-127
Number of pages7
JournalCurrent Opinion in Structural Biology
Issue number1
StatePublished - Feb 2010
Externally publishedYes

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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