Dpo4 is hindered in extending a G.T mismatch by a reverse wobble

Nat Struct Mol Biol. 2004 May;11(5):457-62. doi: 10.1038/nsmb755. Epub 2004 Apr 11.


The ability or inability of a DNA polymerase to extend a mispair directly affects the establishment of genomic mutations. We report here kinetic analyses of the ability of Dpo4, a Y-family polymerase from Sulfolobus solfataricus, to extend from all mispairs opposite a template G or T. Dpo4 is equally inefficient at extending these mispairs, which include, surprisingly, a G.T mispair expected to conform closely to Watson-Crick geometry. To elucidate the basis of this, we solved the structure of Dpo4 bound to G.T-mispaired primer template in the presence of an incoming nucleotide. As a control, we also determined the structure of Dpo4 bound to a matched A-T base pair at the primer terminus. The structures offer a basis for the low efficiency of Dpo4 in extending a G.T mispair: a reverse wobble that deflects the primer 3'-OH away from the incoming nucleotide.

Publication types

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

MeSH terms

  • Bacterial Proteins / chemistry*
  • Base Pair Mismatch*
  • Base Sequence
  • Crystallography, X-Ray
  • DNA Primers
  • Kinetics
  • Models, Molecular
  • Protein Conformation
  • Sulfolobus / enzymology


  • Bacterial Proteins
  • DNA Primers

Associated data

  • PDB/1S97
  • PDB/1S9F