title: hMutSalpha forms an ATP-dependent complex with hMutLalpha and hMutLbeta on DNA.
abstract: The DNA binding properties of hMutSalpha and hMutLalpha and complex formation of hMutSalpha with hMutLalpha and hMutLbeta were investigated using binding experiments on magnetic bead-coupled DNA substrates with nuclear extracts as well as purified proteins. hMutSalpha binding to homoduplex DNA was disrupted by lower NaCl concentrations than hMutSalpha binding to a mismatch. ATP markedly reduced the salt resistance of hMutSalpha binding but hMutSalpha still retained affinity for heteroduplexes. hMutSalpha formed a complex with hMutLalpha and hMutLbeta on DNA in the presence of ATP. This complex only formed on 81mer and not 32mer DNA substrates. Complex formation was enhanced by a mismatch in the DNA substrate, and hMutLalpha and hMutLbeta were shown to enter the complex at different ATP concentrations. Purified hMutLalpha showed an intrinsic affinity for DNA, with a preference for single-stranded over double-stranded DNA.
authors.affiliation: Second Department of Medicine, Johann Wolfgang Goethe-University, Theodor Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Plotz
authors.forename: Jochen
authors.initials: J
authors.lastname: Raedle
authors.forename: Angela
authors.initials: A
authors.lastname: Brieger
authors.forename: Jörg
authors.initials: J
authors.lastname: Trojan
authors.forename: Stefan
authors.initials: S
authors.lastname: Zeuzem
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D020137:Base Pair Mismatch; D015153:Blotting, Western; D002352:Carrier Proteins; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D008280:Magnetics; D008863:Microspheres; D000070976:Mismatch Repair Endonuclease PMS2; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins; D009994:Osmolar Concentration; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C088996:PMS1 protein, human; D021122:Protein Subunits; D011518:Proto-Oncogene Proteins; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; C094934:PMS2 protein, human; C497172:MSH2 protein, human; D000070976:Mismatch Repair Endonuclease PMS2; D000070957:MutL Protein Homolog 1; D000070956:MutL Proteins; D051718:MutS Homolog 2 Protein; D045643:DNA Repair Enzymes