1. Steady-state ATPase activity of E. coli MutS modulated by its dissociation from heteroduplex DNA
- Author
-
Ja Kang Ku, Minseon Cho, Changill Ban, and Seong-Dal Heo
- Subjects
DNA, Bacterial ,congenital, hereditary, and neonatal diseases and abnormalities ,ATPase ,Biophysics ,medicine.disease_cause ,Biochemistry ,chemistry.chemical_compound ,ATP hydrolysis ,MutS-1 ,medicine ,Molecular Biology ,Escherichia coli ,Adenosine Triphosphatases ,DNA clamp ,biology ,Escherichia coli Proteins ,Nucleic Acid Heteroduplexes ,Cell Biology ,MutS DNA Mismatch-Binding Protein ,Enzyme Activation ,chemistry ,biology.protein ,DNA mismatch repair ,DNA ,Heteroduplex - Abstract
The ability of MutS to recognize mismatched DNA is required to initiate a mismatch repair (MMR) system. ATP binding and hydrolysis are essential in this process, but their role in MMR is still not fully understood. In this study, steady-state ATPase activities of MutS from Escherichia coli were investigated using the spectrophotometric method with a double end-blocked heteroduplex containing gapped bases. The ATPase activities of MutS increased as the number of gapped bases increased in a double end-blocked heteroduplex with 2-8 gapped bases in the chain, indicating that MutS dissociates from DNA when it reaches a scission during movement along the DNA. Since movement of MutS along the chain does not require extensive ATP hydrolysis and the ATPase activity is only enhanced when MutS dissociates from a heteroduplex, these results support the sliding clamp model in which ATP binding by MutS induces the formation of a hydrolysis-independent sliding clamp.
- Published
- 2007