The N terminus of Saccharomyces cerevisiae Msh6 is an unstructured tether to PCNA.
The eukaryotic MutS homolog complexes, Msh2-Msh6 and Msh2-Msh3, recognize mismatched bases in DNA during mismatch repair (MMR). The eukaryote-specific N-terminal regions (NTRs) of Msh6 and Msh3 have not been characterized other than by demonstrating that they contain an N-terminal PCNA-interacting motif. Here we have demonstrated genetically that the NTR of Msh6 has an important role in MMR that is partially redundant with PCNA binding. Small-angle X-ray scattering (SAXS) was used to determine the solution structure of the complex of PCNA with Msh2-Msh6 and with the isolated Msh6 NTR, revealing that the Msh6 NTR is a natively disordered domain that forms an extended tether between Msh6 and PCNA. Moreover, computational analysis of PCNA-interacting motifs in the S. cerevisiae proteome indicated that flexible linkers are a common theme for PCNA-interacting proteins that may serve to localize these binding partners without tightly restraining them to the immediate vicinity of PCNA.
Shell
Scarlet S
SS
Ludwig Institute for Cancer Research, University of California, San Diego, School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0669, USA.
Putnam
Christopher D
CD
Kolodner
Richard D
RD
D020137:Base Pair Mismatch; D002850:Chromatography, Gel; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C098790:MSH6 protein, S cerevisiae; D010446:Peptide Fragments; D018809:Proliferating Cell Nuclear Antigen; D029701:Saccharomyces cerevisiae Proteins