Jump to ContentJump to Main Navigation

Biological Chemistry

Editor-in-Chief: Brüne, Bernhard

Editorial Board Member: Buchner, Johannes / Ludwig, Stephan / Sies, Helmut / Turk, Boris / Wittinghofer, Alfred

12 Issues per year

VolumeIssuePage

Issues

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

Citation Information: Biological Chemistry. Volume 383, Issue 6, Pages 969–975, ISSN (Print) 1431-6730, DOI: 10.1515/BC.2002.103, June 2005

Publication History

Published Online:
2005-06-01

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 singlestranded 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.

Comments (0)

Please log in or register to comment.
Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.