Characterization of carcinogen-DNA adducts by means of fluorescence line narrowing spectroscopy
- Iowa State Univ., Ames, IA (United States); and others
Aromatic hydrocarbons like benzo[a]pyrene (BaP) and dibenzo[a,l]pyrene (DBalP) are among the most potent carcinogens presently known. They can be enzymatically activated to, among others, diolepoxides and radical cations. These reactive intermediates have been shown to bind covalently to DNA and form either stable adducts or adducts that depurinate and leave a nick in the DNA. For adduct characterization fluorescence line narrowing (FLN) spectroscopy is a very powerful analytical tool with sub-femtomole sensitivity. After cooling the sample to 4K a laser is used for selective excitation of a subset of molecules (an isochromat) from the broad distribution of molecules in the disordered solvent matrix. The resulting high-resolution fluorescence spectra can reveal both the ground state and the SI excited state vibrational frequencies and serve as a fingerprint for the compound in question. After a brief introduction on the physical background and the required instrumentation, it will be shown that the FLN technique can be applied either directly to whole DNA samples or in combination with HPLC (or PAGE) separation as an off-line identification method. Recently, FLN spectroscopy was used to identify the depurination adducts that resulted from the reaction of DBalP with DNA. FLN can also shed light on the microenvironment of the adduct; allowing one to distinguish between solvent-exposed or intercalated adducts (in oligonucleotides as well as in total DNA). This was used to study how the conformation of stable BaP adducts depends on the stereochemistry of the adduct and on the particular DNA sequence.
- OSTI ID:
- 191730
- Report Number(s):
- CONF-941098-; TRN: 95:006733-0086
- Resource Relation:
- Conference: FACSS XXI: 21st annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS), St. Louis, MO (United States), 2-7 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of 21st annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies; PB: 257 p.
- Country of Publication:
- United States
- Language:
- English
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