Non-covalent intercalative binding of 7,8-dihydroxy-9,10-epoxybenzo(a)pyrene to DNA

Nicholas E. Geacintov, Hiroko Yoshida, Victor Ibanez, Ronald G. Harvey

Research output: Contribution to journalArticlepeer-review


When the benzo(a)pyrene diol epoxide (±)-7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) is mixed into a DNA solution, a 10nm red shift in the absorption maximum of BPDE appears at 354nm which is due to a non-covalent intercalation complex. The major reaction pathway at this intercalation site is the hydrolysis of BPDE to its tetraol which is accompanied by a decrease in the absorbance and a shift from 354 to 353nm (the latter is due to intercalated tetraol). The non-covalent binding constants are approximately 8200M-1 for BPDE and 3300M-1 for the tetraol at 25°C, pH 7.0. Covalent adduct formation between BPDE and DNA occurs either at another, external binding site, or after some rearrangement of the intercalated BPDE, since covalent adducts display a 345nm absorption maximum (2nm red shift only).

Original languageEnglish (US)
Pages (from-to)1569-1577
Number of pages9
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - Jun 30 1981

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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