Summary information and primary citation
- PDB-id
- 6e3w; SNAP-derived features in text and JSON formats;
DNAproDB
- Class
- DNA binding protein-DNA
- Method
- X-ray (2.02 Å)
- Summary
- Structure of human DNA polymerase beta complexed with 8oa in the template base paired with incoming non-hydrolyzable gtp
- Reference
- Koag MC, Jung H, Lee S (2019): "Mutagenic Replication of the Major Oxidative Adenine Lesion 7,8-Dihydro-8-oxoadenine by Human DNA Polymerases." J. Am. Chem. Soc., 141, 4584-4596. doi: 10.1021/jacs.8b08551.
- Abstract
- Reactive oxygen species attack DNA to produce 7,8-dihyro-8-oxoguanine (oxoG) and 7,8-dihydro-8-oxoadenine (oxoA) as major lesions. The structural basis for the mutagenicity of oxoG, which induces G to T mutations, is well understood. However, the structural basis for the mutagenic potential of oxoA, which induces A to C mutations, remains poorly understood. To gain insight into oxoA-induced mutagenesis, we conducted kinetic studies of human DNA polymerases β and η replicating across oxoA and structural studies of polβ incorporating dTTP/dGTP opposite oxoA. While polη readily bypassed oxoA, it incorporated dGTP opposite oxoA with a catalytic specificity comparable to that of correct insertion, underscoring the promutagenic nature of the major oxidative adenine lesion. Polη and polβ incorporated dGTP opposite oxoA ∼170-fold and ∼100-fold more efficiently than that opposite dA, respectively, indicating that the 8-oxo moiety greatly facilitated error-prone replication. Crystal structures of polβ showed that, when paired with an incoming dTTP, the templating oxoA adopted an anti conformation and formed Watson-Crick base pair. When paired with dGTP, oxoA adopted a syn conformation and formed a Hoogsteen base pair with Watson-Crick-like geometry, highlighting the dual-coding potential of oxoA. The templating oxoA was stabilized by Lys280-mediated stacking and hydrogen bonds. Overall, these results provide insight into the mutagenic potential and dual-coding nature of the major oxidative adenine lesion.
