DSSR-PyMOL cartoon-block schematics: PDB entry 5l2g

PDB-id

5l2g; DSSR-derived features in text and JSON formats

Class

DNA

Method

NMR

Summary

Solution structure of a DNA dodecamer with 5-methylcytosine at the 9th position

Reference

Gruber DR, Toner JJ, Miears HL, Shernyukov AV, Kiryutin AS, Lomzov AA, Endutkin AV, Grin IR, Petrova DV, Kupryushkin MS, Yurkovskaya AV, Johnson EC, Okon M, Bagryanskaya EG, Zharkov DO, Smirnov SL (2018): "Oxidative damage to epigenetically methylated sites affects DNA stability, dynamics and enzymatic demethylation." Nucleic Acids Res., 46, 10827-10839. doi: 10.1093/nar/gky893.

Abstract

DNA damage can affect various regulatory elements of the genome, with the consequences for DNA structure, dynamics, and interaction with proteins remaining largely unexplored. We used solution NMR spectroscopy, restrained and free molecular dynamics to obtain the structures and investigate dominant motions for a set of DNA duplexes containing CpG sites permuted with combinations of 5-methylcytosine (mC), the primary epigenetic base, and 8-oxoguanine (oxoG), an abundant DNA lesion. Guanine oxidation significantly changed the motion in both hemimethylated and fully methylated DNA, increased base pair breathing, induced BI→BII transition in the backbone 3' to the oxoG and reduced the variability of shift and tilt helical parameters. UV melting experiments corroborated the NMR and molecular dynamics results, showing significant destabilization of all methylated contexts by oxoG. Notably, some dynamic and thermodynamic effects were not additive in the fully methylated oxidized CpG, indicating that the introduced modifications interact with each other. Finally, we show that the presence of oxoG biases the recognition of methylated CpG dinucleotides by ROS1, a plant enzyme involved in epigenetic DNA demethylation, in favor of the oxidized DNA strand. Thus, the conformational and dynamic effects of spurious DNA oxidation in the regulatory CpG dinucleotide can have far-reaching biological consequences.