Data from: Structural consequence of the most frequently recurring cancer-associated substitution in DNA polymerase ε

The most frequently recurring cancer-associated DNA polymerase ε (Pol ε)
mutation is a P286R substitution in the exonuclease domain. While
originally proposed to increase genome instability by disrupting
exonucleolytic proofreading, the P286R variant was later found to be
significantly more pathogenic than Pol ε proofreading deficiency per se.
The mechanisms underlying its stronger impact remained unclear. Here we
report the crystal structure of the yeast orthologue, Pol ε−P301R,
complexed with DNA and an incoming dNTP. Structural changes in the protein
are confined to the exonuclease domain, with R301 pointing towards the
exonuclease site. Molecular dynamics simulations suggest that R301
interferes with DNA binding to the exonuclease site, an outcome not
observed with the exonuclease-inactive Pol ε−D290A,E292A variant lacking
the catalytic residues. These results reveal a distinct mechanism of
exonuclease inactivation by the P301R substitution and a likely basis for
its dramatically higher mutagenic and tumorigenic effects.