Crystal structure of endonuclease G in complex with DNA reveals how it nonspecifically degrades DNA as a homodimer.

ABSTRACT: Endonuclease G (EndoG) is an evolutionarily conserved mitochondrial protein in eukaryotes that digests nucleus chromosomal DNA during apoptosis and paternal mitochondrial DNA during embryogenesis. Under oxidative stress, homodimeric EndoG becomes oxidized and converts to monomers with diminished nuclease activity. However, it remains unclear why EndoG has to function as a homodimer in DNA degradation. Here, we report the crystal structure of the Caenorhabditis elegans EndoG homologue, CPS-6, in complex with single-stranded DNA at a resolution of 2.3 Å. Two separate DNA strands are bound at the ββα-metal motifs in the homodimer with their nucleobases pointing away from the enzyme, explaining why CPS-6 degrades DNA without sequence specificity. Two obligatory monomeric CPS-6 mutants (P207E a

SUBMITTER: Lin JL 

PROVIDER: S-EPMC5137453 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature