title: Large conformational changes in MutS during DNA scanning, mismatch recognition and repair signalling.
abstract: MutS protein recognizes mispaired bases in DNA and targets them for mismatch repair. Little is known about the transient conformations of MutS as it signals initiation of repair. We have used single-molecule fluorescence resonance energy transfer (FRET) measurements to report the conformational dynamics of MutS during this process. We find that the DNA-binding domains of MutS dynamically interconvert among multiple conformations when the protein is free and while it scans homoduplex DNA. Mismatch recognition restricts MutS conformation to a single state. Steady-state measurements in the presence of nucleotides suggest that both ATP and ADP must be bound to MutS during its conversion to a sliding clamp form that signals repair. The transition from mismatch recognition to the sliding clamp occurs via two sequential conformational changes. These intermediate conformations of the MutS:DNA complex persist for seconds, providing ample opportunity for interaction with downstream proteins required for repair.
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Ruoyi
authors.initials: R
authors.lastname: Qiu
authors.forename: Vanessa C
authors.initials: VC
authors.lastname: DeRocco
authors.forename: Credle
authors.initials: C
authors.lastname: Harris
authors.forename: Anushi
authors.initials: A
authors.lastname: Sharma
authors.forename: Manju M
authors.initials: MM
authors.lastname: Hingorani
authors.forename: Dorothy A
authors.initials: DA
authors.lastname: Erie
authors.forename: Keith R
authors.initials: KR
authors.lastname: Weninger
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry; D053843:DNA Mismatch Repair / Q000235:genetics / Q000502:physiology*; D031541:Fluorescence Resonance Energy Transfer; D051719:MutS DNA Mismatch-Binding Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D051719:MutS DNA Mismatch-Binding Protein