Mismatch-, MutS-, MutL-, and helicase II-dependent unwinding from the single-strand break of an incised heteroduplex.

Journal Article (Journal Article)

Escherichia coli MutS, MutL, and DNA helicase II are sufficient to initiate mismatch-dependent unwinding of an incised heteroduplex (Yamaguchi, M., Dao, V., and Modrich, P. (1998) J. Biol. Chem., 273, 9197-9201). We have studied unwinding of 6.4-kilobase circular G-T heteroduplexes that contain a single-strand incision, 808 base pairs 5' to the mismatch or 1023 base pairs 3' to the mispair as viewed along the shorter path between the two DNA sites. Unwinding of both substrates in the presence of MutS, MutL, DNA helicase II, and single-stranded DNA binding protein was mismatch-dependent and initiated at the single-strand break. Although unwinding occurred in both directions from the strand break, it was biased toward the shorter path linking the strand break and the mispair. MutS and MutL are thus sufficient to coordinate mismatch recognition to the orientation-dependent activation of helicase II unwinding at a single-strand break located a kilobase from the mispair.

Full Text

Duke Authors

Cited Authors

  • Dao, V; Modrich, P

Published Date

  • April 10, 1998

Published In

Volume / Issue

  • 273 / 15

Start / End Page

  • 9202 - 9207

PubMed ID

  • 9535911

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.273.15.9202


  • eng

Conference Location

  • United States