DNA binding properties of the yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers

Karin Drotschmann, Mark C. Hall, Polina V. Shcherbakova, Hong Wang, Dorothy A. Erie, Floyd R. Brownewell, Eric T. Kool, Thomas A. Kunkel

Research output: Contribution to journalShort survey

34 Scopus citations

Abstract

We describe here our recent studies of the DNA binding properties of Msh2-Msh6 and Mlh1-Pms1, two protein complexes required to repair mismatches generated during DNA replication. Mismatched DNA binding by Msh2-Msh6 was probed by mutagenesis based on the crystal structure of the homologous bacterial MutS homodimer bound to DNA. The results suggest that several amino acid side chains inferred to interact with the DNA backbone near the mismatch are critical for repair activity. These contacts, which are different in Msh2 and Msh6, likely facilitate stacking and hydrogen bonding interactions between side chains in Msh6 and the mismatched base, thus stabilizing a kinked DNA conformation that permits subsequent repair steps coordinated by the Mlh1-Pms1 heterodimer. Mlh1-Pms1 also binds to DNA, but independently of a mismatch. Mlh1-Pms1 binds short DNA substrates with low affinity and with a slight preference for single-stranded DNA. It also binds longer duplex DNA molecules, but with a higher affinity indicative of cooperative binding. Indeed, imaging by atomic force microscopy reveals cooperative DNA binding and simultaneous interaction with two DNA duplexes. The novel DNA binding properties of Mlh1-Pms1 may be relevant to signal transduction during DNA mismatch repair and to recombination, meiosis and cellular responses to DNA damage.

Original languageEnglish (US)
Pages (from-to)969-975
Number of pages7
JournalBiological Chemistry
Volume383
Issue number6
DOIs
StatePublished - Aug 23 2002

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Keywords

  • DNA binding
  • Mismatch repair
  • Mlh1
  • Msh2
  • Msh6
  • Pms1

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Clinical Biochemistry

Cite this

Drotschmann, K., Hall, M. C., Shcherbakova, P. V., Wang, H., Erie, D. A., Brownewell, F. R., Kool, E. T., & Kunkel, T. A. (2002). DNA binding properties of the yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers. Biological Chemistry, 383(6), 969-975. https://doi.org/10.1515/BC.2002.103