title: Interaction between the Msh2 and Msh6 nucleotide-binding sites in the Saccharomyces cerevisiae Msh2-Msh6 complex.
abstract: 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.
authors.affiliation: Department of Medicine and Cellular, Cancer Center, Ludwig Institute for Cancer Research, University of California San Diego School of Medicine, La Jolla, California 92093-0669, USA.
authors.forename: Victoria V
authors.initials: VV
authors.lastname: Hargreaves
authors.forename: Scarlet S
authors.initials: SS
authors.lastname: Shell
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Mazur
authors.forename: Martin T
authors.initials: MT
authors.lastname: Hess
authors.forename: Richard D
authors.initials: RD
authors.lastname: Kolodner
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001665:Binding Sites; D003432:Cross-Linking Reagents / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008954:Models, Biological; D008957:Models, Genetic; D008958:Models, Molecular; D051718:MutS Homolog 2 Protein / Q000737:chemistry* / Q000378:metabolism; D009154:Mutation; D009711:Nucleotides / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C098790:MSH6 protein, S cerevisiae; D009711:Nucleotides; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein