hMutSalpha forms an ATP-dependent complex with hMutLalpha and hMutLbeta on DNA

Nucleic Acids Res. 2002 Feb 1;30(3):711-8. doi: 10.1093/nar/30.3.711.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Base Pair Mismatch
  • Blotting, Western
  • Carrier Proteins
  • DNA / genetics
  • DNA / metabolism*
  • DNA Repair Enzymes*
  • DNA-Binding Proteins / metabolism*
  • Dimerization
  • HeLa Cells
  • Humans
  • Macromolecular Substances
  • Magnetics
  • Microspheres
  • Mismatch Repair Endonuclease PMS2
  • MutL Protein Homolog 1
  • MutL Proteins
  • MutS Homolog 2 Protein
  • Neoplasm Proteins / metabolism*
  • Nuclear Proteins
  • Osmolar Concentration
  • Protein Binding
  • Protein Structure, Quaternary
  • Protein Subunits
  • Proto-Oncogene Proteins / metabolism*
  • Thermodynamics

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • DNA-Binding Proteins
  • G-T mismatch-binding protein
  • MLH1 protein, human
  • Macromolecular Substances
  • Neoplasm Proteins
  • Nuclear Proteins
  • PMS1 protein, human
  • Protein Subunits
  • Proto-Oncogene Proteins
  • Adenosine Triphosphate
  • DNA
  • Adenosine Triphosphatases
  • PMS2 protein, human
  • MSH2 protein, human
  • Mismatch Repair Endonuclease PMS2
  • MutL Protein Homolog 1
  • MutL Proteins
  • MutS Homolog 2 Protein
  • DNA Repair Enzymes