Structural and dynamic effects of single 7-hydro-8-oxoguanine bases located in a frameshift target DNA sequence

• Published in: Biophysical chemistry 2005-10, Vol.118 (1), p.31-41
• Main Authors: Barone, Flavia, Lankas, Filip, Spackova, Nada, Sponer, Jiri, Karran, Peter, Bignami, Margherita, Mazzei, Filomena
• Format: Article
• Language: English
• Subjects: 7-hydro-8-oxoguanine; Base Pair Mismatch; Base Sequence; DNA - chemistry; DNA conformation; DNA dynamics; DNA Repair; DNA Replication - drug effects; DNA-Directed DNA Polymerase - genetics; DNA-Directed DNA Polymerase - metabolism; Fluorescence Polarization; Frameshift; Guanine - analogs & derivatives; Guanine - chemistry; Guanine - pharmacology; Hypoxanthine Phosphoribosyltransferase - genetics; Molecular dynamics; Nucleic Acid Conformation - drug effects; Templates, Genetic
• ISSN: 0301-4622; 1873-4200
• DOI: 10.1016/j.bpc.2005.06.003

DNA 7-hydro-8-oxoguanine (8-oxoG) is implicated in frameshift formation in an G 6 sequence of the HPRT gene in mismatch repair (MMR) defective cells. Using oligonucleotides based on this frameshift hotspot, we investigated how a single 8-oxoG modified the structural and dynamic properties of the G 6 tract. A 30 ns molecular dynamics (MD) simulation indicated compression of the minor groove in the immediate vicinity of the lesion. Fluorescence polarization anisotropy (FPA) and MD demonstrated that 8-oxoG increases DNA torsional rigidity and also constrains the movement of the single-stranded region at the single/double stranded DNA junction of model DNA replication template/primer. These constraints influenced the efficiency of primer extension by Klenow (exo −) DNA polymerase.