Interaction between the Msh2 and Msh6 Nucleotide-binding Sites in the Saccharomyces cerevisiae Msh2-Msh6 Complex

• Published in: The Journal of biological chemistry Vol. 285; no. 12; pp. 9301 - 9310
• Main Authors: Hargreaves, Victoria V., Shell, Scarlet S., Mazur, Dan J., Hess, Martin T., Kolodner, Richard D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.03.2010; American Society for Biochemistry and Molecular Biology
• Subjects: Adenosine Triphosphate - chemistry; ATPases; Binding Sites; Cross-Linking Reagents - chemistry; DNA and Chromosomes; DNA Repair; DNA Replication; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; Enzymology; Gene Expression Regulation, Fungal; Models, Biological; Models, Genetic; Models, Molecular; Mutagenesis Mechanisms; Mutation; MutS Homolog 2 Protein - chemistry; MutS Homolog 2 Protein - metabolism; Nucleic Acid Enzymology; Nucleotides - chemistry; Protein Binding; Protein Conformation; Saccharomyces cerevisiae; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - metabolism; Surface Plasmon Resonance; Mutagenesis Mechanisms; DNA Replication; Nucleic Acid Enzymology; ATPases; DNA Repair
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M109.096388

Indirect evidence has suggested that the Msh2-Msh6 mispair-binding complex undergoes conformational changes upon binding of ATP and mispairs, resulting in the formation of Msh2-Msh6 sliding clamps and licensing the formation of Msh2-Msh6-Mlh1-Pms1 ternary complexes. Here, we have studied eight mutant Msh2-Msh6 complexes with defective responses to nucleotide binding and/or mispair binding and used them to study the conformational changes required for sliding clamp formation and ternary complex assembly. ATP binding to the Msh6 nucleotide-binding site results in a conformational change that allows binding of ATP to the Msh2 nucleotide-binding site, although ATP binding to the two nucleotide-binding sites appears to be uncoupled in some mutant complexes. The formation of Msh2-Msh6-Mlh1-Pms1 ternary complexes requires ATP binding to only the Msh6 nucleotide-binding site, whereas the formation of Msh2-Msh6 sliding clamps requires ATP binding to both the Msh2 and Msh6 nucleotide-binding sites. In addition, the properties of the different mutant complexes suggest that distinct conformational states mediated by communication between the Msh2 and Msh6 nucleotide-binding sites are required for the formation of ternary complexes and sliding clamps.