Open AccessPurification, crystallization and preliminary X‐ray diffraction analysis of the human mismatch repair protein MutSβ
Author(s) -
Tseng Quincy,
Orans Jillian,
Hast Michael A.,
Iyer Ravi R.,
Changela Anita,
Modrich Paul L.,
Beese Lorena S.
Publication year - 2011
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309111019300
Subject(s) - dna mismatch repair , heteroduplex , msh6 , msh2 , biology , dna , dna repair , mutant , microbiology and biotechnology , genetics , chemistry , gene
MutSβ is a eukaryotic mismatch repair protein that preferentially targets extrahelical unpaired nucleotides and shares partial functional redundancy with MutSα (MSH2–MSH6). Although mismatch recognition by MutSα has been shown to involve a conserved Phe‐ X ‐Glu motif, little is known about the lesion‐binding mechanism of MutSβ. Combined MSH3/MSH6 deficiency triggers a strong predisposition to cancer in mice and defects in msh2 and msh6 account for roughly half of hereditary nonpolyposis colorectal cancer mutations. These three MutS homologs are also believed to play a role in trinucleotide repeat instability, which is a hallmark of many neurodegenerative disorders. The baculovirus overexpression and purification of recombinant human MutSβ and three truncation mutants are presented here. Binding assays with heteroduplex DNA were carried out for biochemical characterization. Crystallization and preliminary X‐ray diffraction analysis of the protein bound to a heteroduplex DNA substrate are also reported.