6fwk
The crystal structure of Pol2CORE-M644G in complex with DNA and an incoming nucleotideThe crystal structure of Pol2CORE-M644G in complex with DNA and an incoming nucleotide
Structural highlights
FunctionDPOE_YEAST DNA polymerase epsilon (DNA polymerase II) participates in chromosomal DNA replication. It is required during synthesis of the leading and lagging DNA strands at the replication fork and binds at/or near replication origins and moves along DNA with the replication fork. It has 3'-5' proofreading exonuclease activity that correct errors arising during DNA replication. It is also involved in DNA synthesis during DNA repair.[1] Publication Abstract from PubMedThe most frequently recurring cancer-associated DNA polymerase epsilon (Pol epsilon) 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 epsilon proofreading deficiency per se. The mechanisms underlying its stronger impact remained unclear. Here we report the crystal structure of the yeast orthologue, Pol epsilon-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 epsilon-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. Structural consequence of the most frequently recurring cancer-associated substitution in DNA polymerase epsilon.,Parkash V, Kulkarni Y, Ter Beek J, Shcherbakova PV, Kamerlin SCL, Johansson E Nat Commun. 2019 Jan 22;10(1):373. doi: 10.1038/s41467-018-08114-9. PMID:30670696[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
|