The fluorescence emission properties of dGuo-C8-AAF, dGuo-C8-AF and the imidazole ring-opened products of dGuo-C8-AF indicate a different dynamic structure for the various compounds.
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-(deoxy-guanosin-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 F congruent to 4-5 X 10(-4) shows a broad and structureless emission band, which is attributed to the formation of an excited-state complex. In contrast, the emission spectra of dGuo-C8-AAF (phi F congruent to 1.10(-4] and both ro-dGuo-C8-AF compounds [phi F(ro-dGuo-C8-AF I) congruent to 4.10(-3); phi F(ro-dGuo-C8-AF II) congruent to 4.10(-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.
van Houte
L P
LP
Free University, Department of Biophysics, The Netherlands.
Retèl
J
J
Westra
J G
JG
van Grondelle
R
R
D015073:2-Acetylaminofluorene / Q000031:analogs & derivatives; D002942:Circular Dichroism; D003849:Deoxyguanosine / Q000031:analogs & derivatives*; D005449:Fluorenes; D005453:Fluorescence; D007093:Imidazoles; D015394:Molecular Structure
D005449:Fluorenes; D007093:Imidazoles; C031838:N-(deoxyguanosin-8-yl)-2-aminofluorene; C018776:N-(deoxyguanosin-8-yl)acetylaminofluorene; D015073:2-Acetylaminofluorene; D003849:Deoxyguanosine