Processing of DNA single-strand breaks with oxidatively damaged ends by LIG1.

ABSTRACT: DNA ligase 1 (LIG1) seals broken strand breaks by joining two adjacent ends during DNA replication and repair transactions. We previously reported atomic-level insight into the strategies that LIG1 uses to discriminate mismatches or ribonucleotides. However, how LIG1 processes strand breaks with oxidatively damaged ends in the absence and presence of a "wrong" sugar remains unknown. Here, we determined the crystal structures of LIG1/nick DNA complexes with 3'-8-oxodG and 3'-8-oxorG templating A or C during the pre- and post-catalytic steps of the ligation reaction. Our structures demonstrated differences in the distances at the +1 and +2 nucleotides relative to the 3'-end of the nick and a shift in the template base position to accommodate the oxidative lesion depending on the dual coding

SUBMITTER: Balu KE 

PROVIDER: S-EPMC12693511 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature