Fluorescence Probing of Aminofluorene-Induced Conformational Heterogeneity in DNA Duplexes

Authors

Nidhi Jain, University of Rhode Island
Yana K. Reshetnyak, University of Rhode IslandFollow
Lan Gao
M. Paul Chiarelli
Bongsup P. Cho, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

2008

Abstract

Fluorescence spectroscopy was used to study carcinogen-induced conformational heterogeneity in DNA duplexes. The fluorophore 2-aminopurine (AP) was incorporated adjacent (5′) to the lesion (G*) in eight different DNA duplexes [d(5′-CTTCTPG*NCCTC-3′):d(5′-GAGGNXTAGAAG-3′), G* = FAF adduct, P = AP, N = G, A, C, T, and X = C, A] modified by FAF [N-(2′-deoxyguanosin-8-yl)-7-fluoro-2-aminofluorene], a fluorine-tagged model DNA adduct derived from the potent carcinogen 2-aminofluorene. Steady-state measurements showed that fluorescence intensity and Stern−Volmer constants (K_sv) derived from acrylamide quenching experiments decreased for all carcinogen-modified duplexes relative to the controls, which suggests greater AP stacking in the duplex upon adduct formation. Conformation-specific stacking of AP with the neighboring adduct was evidenced by a sequence-dependent variation in fluorescence intensity, position of emission maximum, degree of emission quenching by acrylamide, and temperature-dependent spectral changes. The magnitude of stacking was in the order of FAF residue in base-displaced stacked (S) > minor groove wedged (W) > major groove B type (B). This work represents a novel utility of AP in probing adduct-induced conformational heterogeneities in DNA duplexes.

Citation/Publisher Attribution

Jain, N., Reshetnyak, Y. K., Gao, L., Chiarelli, M. P., & Cho, B. P. (2008). Fluorescence Probing of Aminofluorene-Induced Conformational Heterogeneity in DNA Duplexes. Chem. Res. Toxicol., 28(2), 445-452. doi: 10.1021/tx7003536

Available at: https://doi.org/10.1021/tx7003536