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.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
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Research Support, N.I.H., Intramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / chemistry
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Adaptor Proteins, Signal Transducing / drug effects*
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Adenine Nucleotides / pharmacology*
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Adenosine Diphosphate / pharmacology
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / classification
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Adenosine Triphosphatases / drug effects*
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Adenosine Triphosphatases / metabolism
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Adenosine Triphosphatases / ultrastructure
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Adenosine Triphosphate / analogs & derivatives
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Adenosine Triphosphate / pharmacology
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Adenylyl Imidodiphosphate / pharmacology
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Base Pair Mismatch
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Carrier Proteins / chemistry
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Carrier Proteins / drug effects*
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Carrier Proteins / ultrastructure
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Circular Dichroism
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DNA Repair Enzymes / chemistry
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DNA Repair Enzymes / drug effects*
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DNA Repair Enzymes / ultrastructure
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / drug effects*
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DNA-Binding Proteins / ultrastructure
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Dimerization
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Humans
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Hydrolysis
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Microscopy, Atomic Force*
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Mismatch Repair Endonuclease PMS2
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Models, Molecular
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MutL Protein Homolog 1
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MutL Proteins
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Protein Binding
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Protein Conformation / drug effects
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Protein Structure, Secondary / drug effects
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / drug effects*
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Saccharomyces cerevisiae Proteins / ultrastructure
Substances
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Adaptor Proteins, Signal Transducing
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Adenine Nucleotides
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Carrier Proteins
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DNA-Binding Proteins
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MLH1 protein, S cerevisiae
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MutLalpha protein, human
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PMS1 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Adenylyl Imidodiphosphate
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adenosine 5'-O-(3-thiotriphosphate)
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Adenosine Diphosphate
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Adenosine Triphosphate
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Adenosine Triphosphatases
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PMS2 protein, human
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Mismatch Repair Endonuclease PMS2
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MutL Protein Homolog 1
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MutL Proteins
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DNA Repair Enzymes