LOCATION OF EXCIMER-FORMING ADDUCTS OF (+)-ANTI-BENZO A PYRENE DIOL EPOXIDE IN DNA
Artikel i vetenskaplig tidskrift, 1993

Covalent adducts of the carcinogenic polycyclic aromatic hydrocarbon (+)-anti-benzo[a]pyrene 7,8-dihydrodiol 9,10-epoxide ((+)-anti-BPDE) in polynucleotides have been studied by fluorescence spectroscopy. The pyrenyl chromophores of the BPDE adducts, linked by the C10 atom to the exocyclic nitrogen of guanine, interact in the photoexcited state, as evidenced by excimer fluorescence. Strong BPDE excimer fluorescence is observed in the alternating poly(dGdC).poly(dGdC) sequence, whereas it is weak in the homopolymeric poly(dG).poly(dC) and in calf thymus DNA. No excimer fluorescence is observed for the BPDE adducts in poly(dAdC).poly(dGdT) or poly(dAdG).poly(dCdT). It is concluded that the formation of BPDE excimers in polynucleotides requires binding to guanines on different strands on consecutive basepairs. The experimental results are supported by graphics modeling and energy minimization of BPDE adducts in various oligonucleotide sequences. The results show that the most favorable arrangement for excimer formation of the BPDE-dG adducts is in a 5'(dCdG-BPDE).5'(dCdG-BPDE) sequence, where the pyrenyl chromophores interact in the minor groove.

molecular mechanics

binding

linear dichroism

benzo<a>pyrene

fluorescence

poly(dg-dc)

covalent complexes

Författare

M. Eriksson

Seog K. Kim

Institutionen för fysikalisk kemi

S. Sen

A. Graslund

B. Jernstrom

Bengt Nordén

Institutionen för fysikalisk kemi

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 115 1639-1644

Ämneskategorier

Kemi

DOI

10.1021/ja00058a004