title: MutS stimulates the endonuclease activity of MutL in an ATP-hydrolysis-dependent manner.
abstract: In the initial steps of DNA mismatch repair, MutS recognizes a mismatched base and recruits the latent endonuclease MutL onto the mismatch-containing DNA in concert with other proteins. MutL then cleaves the error-containing strand to introduce an entry point for the downstream excision reaction. Because MutL has no intrinsic ability to recognize a mismatch and discriminate between newly synthesized and template strands, the endonuclease activity of MutL is strictly regulated by ATP-binding in order to avoid nonspecific degradation of the genomic DNA. However, the activation mechanism for its endonuclease activity remains unclear. In this study, we found that the coexistence of a mismatch, ATP and MutS unlocks the ATP-binding-dependent suppression of MutL endonuclease activity. Interestingly, ATPase-deficient mutants of MutS were unable to activate MutL. Furthermore, wild-type MutS activated ATPase-deficient mutants of MutL less efficiently than wild-type MutL. We concluded that ATP hydrolysis by MutS and MutL is involved in the mismatch-dependent activation of MutL endonuclease activity.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Suita, Osaka, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Shimada
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kawasoe
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Hata
authors.forename: Tatsuro S
authors.initials: TS
authors.lastname: Takahashi
authors.forename: Ryoji
authors.initials: R
authors.lastname: Masui
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Kenji
authors.initials: K
authors.lastname: Fukui
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000737:chemistry*; D053843:DNA Mismatch Repair; D004789:Enzyme Activation; D006868:Hydrolysis; D007700:Kinetics; D051719:MutS DNA Mismatch-Binding Protein / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D017434:Protein Structure, Tertiary; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein
keywords: ATP hydrolysis; DNA mismatch repair; MutL; MutS; endonuclease activity