Observing translesion synthesis of an aromatic amine DNA adduct by a high-fidelity DNA polymerase

J Biol Chem. 2004 Nov 26;279(48):50280-5. doi: 10.1074/jbc.M409224200. Epub 2004 Sep 22.


Aromatic amines have been studied for more than a half-century as model carcinogens representing a class of chemicals that form bulky adducts to the C8 position of guanine in DNA. Among these guanine adducts, the N-(2'-deoxyguanosin-8-yl)-aminofluorene (G-AF) and N-2-(2'-deoxyguanosin-8-yl)-acetylaminofluorene (G-AAF) derivatives are the best studied. Although G-AF and G-AAF differ by only an acetyl group, they exert different effects on DNA replication by replicative and high-fidelity DNA polymerases. Translesion synthesis of G-AF is achieved with high-fidelity polymerases, whereas replication of G-AAF requires specialized bypass polymerases. Here we have presented structures of G-AF as it undergoes one round of accurate replication by a high-fidelity DNA polymerase. Nucleotide incorporation opposite G-AF is achieved in solution and in the crystal, revealing how the polymerase accommodates and replicates past G-AF, but not G-AAF. Like an unmodified guanine, G-AF adopts a conformation that allows it to form Watson-Crick hydrogen bonds with an opposing cytosine that results in protrusion of the bulky fluorene moiety into the major groove. Although incorporation opposite G-AF is observed, the C:G-AF base pair induces distortions to the polymerase active site that slow translesion synthesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amines / metabolism*
  • DNA / biosynthesis*
  • DNA Adducts / biosynthesis*
  • DNA-Directed DNA Polymerase / metabolism*
  • Deoxyguanosine / analogs & derivatives*


  • Amines
  • DNA Adducts
  • DNA
  • DNA-Directed DNA Polymerase
  • Deoxyguanosine

Associated data

  • PDB/1UA0
  • PDB/1UA1