Structure of a high fidelity DNA polymerase bound to a benzo[a]pyrene adduct that blocks replication

Gerald W. Hsu, Xuanwei Huang, Natalia P. Luneva, Nicholas E. Geacintov, Lorena S. Beese

Research output: Contribution to journalArticlepeer-review


Of the carcinogens to which humans are most frequently exposed, the polycyclic aromatic hydrocarbon benzo[a]pyrene (BP) is one of the most ubiquitous. BP is a byproduct of grilled foods and tobacco and fuel combustion and has long been linked to various human cancers, particularly lung and skin. BP is metabolized to diol epoxides that covalently modify DNA bases to form bulky adducts that block DNA synthesis by replicative or high fidelity DNA polymerases. Here we present the structure of a high fidelity polymerase from a thermostable strain of Bacillus stearothermophilus (Bacillus fragment) bound to the most common BP-derived N2-guanine adduct base-paired with cytosine. The BP adduct adopts a conformation that places the polycyclic BP moiety in the nascent DNA minor groove and is the first structure of a minor groove adduct bound to a polymerase. Orientation of the BP moiety into the nascent DNA minor groove results in extensive disruption to the interactions between the adducted DNA duplex and the polymerase. The disruptions revealed by the structure of Bacillus fragment bound to a BP adduct provide a molecular basis for rationalizing the potent blocking effect on replication exerted by BP adducts.

Original languageEnglish (US)
Pages (from-to)3764-3770
Number of pages7
JournalJournal of Biological Chemistry
Issue number5
StatePublished - Feb 4 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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