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Assembly and molecular activities of the MutS tetramer.

Publication ,  Journal Article
Bjornson, KP; Blackwell, LJ; Sage, H; Baitinger, C; Allen, D; Modrich, P
Published in: J Biol Chem
September 5, 2003

Analytical equilibrium ultracentrifugation indicates that Escherichia coli MutS exists as an equilibrating mixture of dimers and tetramers. The association constant for the dimer-to-tetramer transition is 2.1 x 10(7) M-1, indicating that the protein would consist of both dimers and tetramers at physiological concentrations. The carboxyl terminus of MutS is required for tetramer assembly because a previously described 53-amino acid carboxyl-terminal truncation (MutS800) forms a limiting species of a dimer (Obmolova, G., Ban, C., Hsieh, P., and Yang, W. (2000) Nature 407, 703-710; Lamers, M. H., Perrakis, A., Enzlin, J. H., Winterwerp, H. H., de Wind, N., and Sixma, T. K. (2000) Nature 407, 711-717). MutS800 binds a 20-base pair heteroduplex an order of magnitude more weakly than full-length MutS, and at saturating protein concentrations, the heteroduplex-bound mass observed with MutS800 is only half that observed with the full length protein, indicating that the subunit copy number of heteroduplex-bound MutS is twice that of MutS800. Analytical equilibrium ultracentrifugation using a fluorescein-tagged 20-base pair heteroduplex demonstrated that native MutS forms a tetramer on this single site-sized heteroduplex DNA. Equilibrium fluorescence experiments indicated that dimer-to-tetramer assembly promotes mismatch binding by MutS and that the tetramer can bind only a single heteroduplex molecule, implying nonequivalence of the two dimers within the tetramer. Compared with native MutS, the ability of MutS800 to promote MutL-dependent activation of MutH is substantially reduced.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

September 5, 2003

Volume

278

Issue

36

Start / End Page

34667 / 34673

Location

United States

Related Subject Headings

  • Ultracentrifugation
  • Surface Plasmon Resonance
  • Spectrometry, Fluorescence
  • Protein Structure, Tertiary
  • MutS DNA Mismatch-Binding Protein
  • Escherichia coli Proteins
  • Escherichia coli
  • Endodeoxyribonucleases
  • Dose-Response Relationship, Drug
  • Dimerization
 

Citation

APA
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ICMJE
MLA
NLM
Bjornson, K. P., Blackwell, L. J., Sage, H., Baitinger, C., Allen, D., & Modrich, P. (2003). Assembly and molecular activities of the MutS tetramer. J Biol Chem, 278(36), 34667–34673. https://doi.org/10.1074/jbc.M305513200
Bjornson, Keith P., Leonard J. Blackwell, Harvey Sage, Celia Baitinger, Dwayne Allen, and Paul Modrich. “Assembly and molecular activities of the MutS tetramer.J Biol Chem 278, no. 36 (September 5, 2003): 34667–73. https://doi.org/10.1074/jbc.M305513200.
Bjornson KP, Blackwell LJ, Sage H, Baitinger C, Allen D, Modrich P. Assembly and molecular activities of the MutS tetramer. J Biol Chem. 2003 Sep 5;278(36):34667–73.
Bjornson, Keith P., et al. “Assembly and molecular activities of the MutS tetramer.J Biol Chem, vol. 278, no. 36, Sept. 2003, pp. 34667–73. Pubmed, doi:10.1074/jbc.M305513200.
Bjornson KP, Blackwell LJ, Sage H, Baitinger C, Allen D, Modrich P. Assembly and molecular activities of the MutS tetramer. J Biol Chem. 2003 Sep 5;278(36):34667–34673.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

September 5, 2003

Volume

278

Issue

36

Start / End Page

34667 / 34673

Location

United States

Related Subject Headings

  • Ultracentrifugation
  • Surface Plasmon Resonance
  • Spectrometry, Fluorescence
  • Protein Structure, Tertiary
  • MutS DNA Mismatch-Binding Protein
  • Escherichia coli Proteins
  • Escherichia coli
  • Endodeoxyribonucleases
  • Dose-Response Relationship, Drug
  • Dimerization