The fluorescence emission properties of dGuo-C8-AAF, dGuo-C8AF and the imidazole ring-opened products of dGuo-C8-AF indicate a different dynamic structure for the various compounds

• Published in: Carcinogenesis (New York) 1990-01, Vol.11 (4), p.701-704
• Main Authors: van Houte, LPA, Retel, J, Westra, J G, van Grondelle, R
• Format: Article
• Language: English
• ISSN: 0143-3334

The reactive metabolites of the carcinogenic N-acetyl-2-aminofluorene (AAF) form adducts with the guanine base of DNA. The fluorescence emission characteristics of N-(deoxyguanosin-8-yl)-N-acetyl-2-aminofluorene (dGuo-C8-AAF), N-(deoxyguanosin-8-yl)-2-aminofluorene (dGuo-C8-AF) and the two N7 = C8 imidazole ring-opened products of dGuo-C8-AF (ro-dGuo-C8-AF I + II) were investigated and related to their conformational properties. The dGuo-C8-AF adduct ( Phi sub(F) approximately equals 4-5 x 10 super(-4)) shows a broad and structureless emission band, which is attributed to the formation of an excited-state complex. The emission spectra of dGuo-C8-AAF ( Phi sub(F) approximately equals 1.10 super(-4)) and both ro-dGuo-C8-AF compounds ( Phi sub(F)(ro-dGuo-C8-AF I) approximately equals 4.10 super(-3); Phi sub(F)(ro-dGuo-C8-AF II) approximately equals 4.10 super(4)) are narrow. This indicates that dGuo-C8-AAF and ro-dGuo-C8-AF I + II do not decay into an exciplex as occurs in dGuo-C8-AF. The spectroscopic features are discussed in terms of the differences in the dynamic structure of the various compounds.