Skip to main content
Journal cover image

Modulation of MutS ATP hydrolysis by DNA cofactors.

Publication ,  Journal Article
Bjornson, KP; Allen, DJ; Modrich, P
Published in: Biochemistry
March 21, 2000

Escherichia coli MutS protein, which is required for mismatch repair, has a slow ATPase activity that obeys Michalelis-Menten kinetics. At 37 degrees C, the steady-state turnover rate for ATP hydrolysis is 1.0 +/- 0.3 min(-1) per monomer equivalent with a K(m) of 33 +/- 6 microM. Hydrolysis is competitively inhibited by the ATP analogues AMPPNP and ATPgammaS, with K(i) values of 4 microM in both cases, and by ADP with a K(i) of 40 microM. The rate of ATP hydrolysis is stimulated 2-5-fold by short hetero- and homoduplex DNAs. The concentration of DNA cofactor that yields half-maximal stimulation is lowest for oligodeoxynucleotide duplexes that contain a mismatched base pair. Pre-steady-state chemical quench analysis has demonstrated a substoichiometric initial burst of ADP formation by free MutS that is governed by a rate constant of 78 min(-1), indicating that the rate-limiting step for the steady-state reaction occurs after hydrolysis. Prebinding of MutS to homoduplex DNA does not alter the burst kinetics or amplitude but only increases the steady-state rate. In contrast, binding of the protein to heteroduplex DNA abolishes the burst of ADP formation, indicating that the rate-limiting step now occurs before hydrolysis. Gel filtration analysis indicates that the MutS dimer assembles into higher order oligomers in a concentration-dependent manner, and that ATP binding shifts this equilibrium to favor assembly. These results, together with kinetic findings, indicate nonequivalence of subunits within a MutS oligomer with respect to ATP hydrolysis and DNA binding.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

March 21, 2000

Volume

39

Issue

11

Start / End Page

3176 / 3183

Location

United States

Related Subject Headings

  • Nucleic Acid Heteroduplexes
  • MutS DNA Mismatch-Binding Protein
  • Kinetics
  • Hydrolysis
  • Escherichia coli Proteins
  • Escherichia coli
  • Dimerization
  • DNA-Binding Proteins
  • DNA, Bacterial
  • DNA Repair
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Bjornson, K. P., Allen, D. J., & Modrich, P. (2000). Modulation of MutS ATP hydrolysis by DNA cofactors. Biochemistry, 39(11), 3176–3183. https://doi.org/10.1021/bi992286u
Bjornson, K. P., D. J. Allen, and P. Modrich. “Modulation of MutS ATP hydrolysis by DNA cofactors.Biochemistry 39, no. 11 (March 21, 2000): 3176–83. https://doi.org/10.1021/bi992286u.
Bjornson KP, Allen DJ, Modrich P. Modulation of MutS ATP hydrolysis by DNA cofactors. Biochemistry. 2000 Mar 21;39(11):3176–83.
Bjornson, K. P., et al. “Modulation of MutS ATP hydrolysis by DNA cofactors.Biochemistry, vol. 39, no. 11, Mar. 2000, pp. 3176–83. Pubmed, doi:10.1021/bi992286u.
Bjornson KP, Allen DJ, Modrich P. Modulation of MutS ATP hydrolysis by DNA cofactors. Biochemistry. 2000 Mar 21;39(11):3176–3183.
Journal cover image

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

March 21, 2000

Volume

39

Issue

11

Start / End Page

3176 / 3183

Location

United States

Related Subject Headings

  • Nucleic Acid Heteroduplexes
  • MutS DNA Mismatch-Binding Protein
  • Kinetics
  • Hydrolysis
  • Escherichia coli Proteins
  • Escherichia coli
  • Dimerization
  • DNA-Binding Proteins
  • DNA, Bacterial
  • DNA Repair