Fluorescence and photoelectron studies of the intercalative binding of benz(a)anthracene metabolite models to DNA

• Published in: Biochemical and biophysical research communications Vol. 112; no. 1; pp. 1 - 7
• Main Authors: Shahbaz, M., Harvey, R.G., Prakash, A.S., Boal, T.R., Zegar, I.S., LeBreton, P.R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.04.1983
• Subjects: Benz(a)Anthracenes - metabolism; Binding Sites; DNA - metabolism; Electrons; Photochemistry; Spectrometry, Fluorescence
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(83)91788-6

DNA binding of nonreactive metabolite models derived from benz(a)anthracene was studied. The molecules investigated include 1,2,3,4-tetrahydrobenz(a)anthracene ( 1 ), 5,6-dihydrobenz(a)anthracene ( 2 ), and 8,9,10,11-tetrahydrobenz(a)anthracene ( 3 ), as well as anthracene and phenan − threne. Measurements of the effects of DNA binding upon fluorescence intensities and fluorescence lifetimes indicate that molecules 1 and 3 (K A = 1.5–2.5×10 3 M −1) bind more strongly to native DNA than does molecule 2 (K A ⋍ 0.5×10 3 M −1). Furthermore, molecules 1 and 3 bind to DNA much more effectively than do the two less sterically hindered π electron metabolite models, anthracene and phenanthrene. Photoelectron data suggests that the enhanced binding of molecules 1 and 3 is due to increases in polarizability. Experiments carried out with denatured DNA indicate that the binding of molecule 1 entails the greatest intercalation.