Download MendeleyMechanism of Error-Free Bypass of the Environmental Carcinogen N-(2'-Deoxyguanosin-8-yl)-3-aminobenzanthrone Adduct by Human DNA Polymerase eta.
Patra, A., Politica, D.A., Chatterjee, A., Tokarsky, E.J., Suo, Z., Basu, A.K., Stone, M.P., Egli, M.(2016) Chembiochem 17: 2033-2037
- PubMed: 27556902
- DOI: https://doi.org/10.1002/cbic.201600420
- Primary Citation of Related Structures:
5JUM - PubMed Abstract:
The environmental pollutant 3-nitrobenzanthrone produces bulky aminobenzanthrone (ABA) DNA adducts with both guanine and adenine nucleobases. A major product occurs at the C8 position of guanine (C8-dG-ABA). These adducts present a strong block to replicative polymerases but, remarkably, can be bypassed in a largely error-free manner by the human Y-family polymerase η (hPol η). Here, we report the crystal structure of a ternary Pol⋅DNA⋅dCTP complex between a C8-dG-ABA-containing template:primer duplex and hPol η. The complex was captured at the insertion stage and provides crucial insight into the mechanism of error-free bypass of this bulky lesion. Specifically, bypass involves accommodation of the ABA moiety inside a hydrophobic cleft to the side of the enzyme active site and formation of an intra-nucleotide hydrogen bond between the phosphate and ABA amino moiety, allowing the adducted guanine to form a standard Watson-Crick pair with the incoming dCTP.
Organizational Affiliation:
Department of Biochemistry, Vanderbilt University, School of Medicine, 868A Robinson Research Building, Nashville, TN, 37232, USA.
