Characterization of tetrol I-1 and (+/-)-anti-BPDE-DNA adducts with solid-matrix fluorescence quenching.

Abstract

The solid-matrix fluorescence (SMF) quenching of (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts and a hydrolysis product of the DNA adducts, tetrol I-1, were investigated by using thallium nitrate and sodium iodide to quench the SMF. Several fluorescence quenching models were evaluated for both (+/-)-anti-BPDE-DNA adducts and tetrol I-1. The SMF quenching phenomena were quite different with the two salts for the (+/-)-anti-BPDE-DNA adducts and tetrol I-1. Generally, with thallium nitrate as a quencher, a two-site model with two independent quenching sites was applicable to both the (+/-)-anti-BPDE-DNA adducts and tetrol I-1 data. However, with sodium iodide, the SMF quenching data for tetrol I-1 were fit to the sphere of action model, but the (+/-)-anti-BPDE-DNA adducts SMF quenching data were qualitatively related to a BET isotherm. From the SMF quenching data, unique information was acquired for the quasi-intercalated BPDE-DNA adducts and the external form of the BPDE-DNA adducts. In addition, insights were obtained on how the adsorbed salts interacted with the solid matrix and with the (+/-)-anti-BPDE-DNA adducts and tetrol I-1.