Open AccessSharp kinking of a coiled-coil in MutS allows DNA binding and release
Author(s) -
D. Bhairosing-Kok,
F.S. Groothuizen,
Alexander Fish,
Shreya Dharadhar,
H.H.K. Winterwerp,
Titia K. Sixma
Publication year - 2019
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gkz649
Subject(s) - biology , dna , coiled coil , dna mismatch repair , dna clamp , biophysics , hmg box , dna replication , replisome , dna repair , dna binding protein , microbiology and biotechnology , genetics , circular bacterial chromosome , gene , polymerase chain reaction , transcription factor , reverse transcriptase
DNA mismatch repair (MMR) corrects mismatches, small insertions and deletions in DNA during DNA replication. While scanning for mismatches, dimers of MutS embrace the DNA helix with their lever and clamp domains. Previous studies indicated generic flexibility of the lever and clamp domains of MutS prior to DNA binding, but whether this was important for MutS function was unknown. Here, we present a novel crystal structure of DNA-free Escherichia coli MutS. In this apo-structure, the clamp domains are repositioned due to kinking at specific sites in the coiled-coil region in the lever domains, suggesting a defined hinge point. We made mutations at the coiled-coil hinge point. The mutants made to disrupt the helical fold at the kink site diminish DNA binding, whereas those made to increase stability of coiled-coil result in stronger DNA binding. These data suggest that the site-specific kinking of the coiled-coil in the lever domain is important for loading of this ABC-ATPase on DNA.