title: Direct visualization of asymmetric adenine-nucleotide-induced conformational changes in MutL alpha.
abstract: MutL alpha, the heterodimeric eukaryotic MutL homolog, is required for DNA mismatch repair (MMR) in vivo. It has been suggested that conformational changes, modulated by adenine nucleotides, mediate the interactions of MutL alpha with other proteins in the MMR pathway, coordinating the recognition of DNA mismatches by MutS alpha and the activation of MutL alpha with the downstream events that lead to repair. Thus far, the only evidence for these conformational changes has come from X-ray crystallography of isolated domains, indirect biochemical analyses, and comparison to other members of the GHL ATPase family to which MutL alpha belongs. Using atomic force microscopy (AFM), coupled with biochemical techniques, we demonstrate that adenine nucleotides induce large asymmetric conformational changes in full-length yeast and human MutL alpha and that these changes are associated with significant increases in secondary structure. These data reveal an ATPase cycle in which sequential nucleotide binding, hydrolysis, and release modulate the conformational states of MutL alpha.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Sacho
authors.forename: Farid A
authors.initials: FA
authors.lastname: Kadyrov
authors.forename: Paul
authors.initials: P
authors.lastname: Modrich
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kunkel
authors.forename: Dorothy A
authors.initials: DA
authors.lastname: Erie
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000187:drug effects*; D000227:Adenine Nucleotides / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000145:classification / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D020137:Base Pair Mismatch; D002352:Carrier Proteins / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D002942:Circular Dichroism; D045643:DNA Repair Enzymes / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D019281:Dimerization; D006801:Humans; D006868:Hydrolysis; D018625:Microscopy, Atomic Force; D000070976:Mismatch Repair Endonuclease PMS2; D008958:Models, Molecular; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D017433:Protein Structure, Secondary / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000227:Adenine Nucleotides; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C088859:MLH1 protein, S cerevisiae; C500929:MutLalpha protein, human; C088858:PMS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000266:Adenylyl Imidodiphosphate; C022571:adenosine 5'-O-(3-thiotriphosphate); D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C094934:PMS2 protein, human; D000070976:Mismatch Repair Endonuclease PMS2; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D045643:DNA Repair Enzymes