MutS and MutL activate DNA helicase II in a mismatch-dependent manner.

Journal Article (Journal Article)

MutS, MutL, and DNA helicase II are required for the mismatch-provoked excision step that occurs during Escherichia coli methyl-directed mismatch repair. In this study MutL is shown to enhance the unwinding activity of DNA helicase II more than 10-fold on a conventional helicase substrate in which a 35-residue oligonucleotide is annealed to a M13 circular single-stranded phage DNA under conditions where the two proteins are present at approximately molar stoichiometry with respect to the substrate. MutS- and MutL-dependent activation of DNA helicase II has also been demonstrated with a model substrate in which a 138-residue oligonucleotide was hybridized to a 138-nucleotide gap in an otherwise duplex 7,100-base pair circular DNA. Displacement of the oligonucleotide requires MutS, MutL, DNA helicase II, and ATP and is dependent on the presence of a mismatch within the hybrid region. Although DNA helicase II and Rep helicase share substantial sequence homology and features of mechanism, Rep helicase is inactive in this reaction.

Full Text

Duke Authors

Cited Authors

  • Yamaguchi, M; Dao, V; Modrich, P

Published Date

  • April 10, 1998

Published In

Volume / Issue

  • 273 / 15

Start / End Page

  • 9197 - 9201

PubMed ID

  • 9535910

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.273.15.9197


  • eng

Conference Location

  • United States