Conformational studies of the (+)-trans, (-)-trans, (+)-cis, and (-)-cis adducts of anti-benzo[a]pyrene diolepoxide to N2-dG in duplex oligonucleotides using polyacrylamide gel electrophoresis and low-temperature fluorescence spectroscopy

Myungkoo Suh, Freek Ariese, Gerald J. Small, Ryszard Jankowiak, Tong Ming Liu, Nicholas Geacintov

Research output: Contribution to journalArticle

Abstract

Using polyacrylamide gel electrophoresis (PAGE) and low-temperature, laser-induced fluorescence line narrowing (FLN) and non-line narrowing (NLN) spectroscopic methods, the conformational characteristics of stereochemically defined and site-specific adducts derived from the binding of 7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE, a metabolite of the environmental carcinogen benzo[a]pyrene), to DNA were studied. The focus of these studies was on the four stereochemically distinct anti-BPDE modified duplexes 5′-d(CCATCGCTACC) · (GGTAGCGATGG), where G denotes the lesion site derived from trans or cis addition of the exocyclic amino group of guanine to the C10 position of either (+) or (-)-anti-BPDE. PAGE experiments under non-denaturing conditions showed that the (+)-trans adduct causes a significantly greater retardation in the electrophoretic mobility than the other three adducts, probably the result of important adduct-induced distortions of the duplex structure. Low-temperature fluorescence studies in frozen aqueous buffer matrices showed that the (+)-trans adduct adopts primarily an external conformation with only minor interactions with the helix, but a smaller fraction (∼ 25%) appears to exists in a partially base-stacked conformation. The (-)-trans adduct exists almost exclusively (∼ 97%) in an external conformation. Both cis adducts were found to be intercalated; strong electron-phonon coupling observed in their FLN spectra provided additional evidence for significant π-π stacking interactions between the pyrenyl residues and the bases. FLN spectroscopy is shown to be suitable for distinguishing between trans and cis adducts, but lesions with either (+)- or (-)-trans, or (+)- or (-)-cis stereochemical characteristics showed very similar vibrational patterns. Addition of glycerol (50%, v/v) to the matrix caused a partial disruption of the chromophore-base stacking interactions for most adducts, but the (-)-cis isomer showed a strong blue-shift and unusual vibrational frequencies. Low-temperature fluorescence spectroscopy techniques are most suitable for distinguishing between different conformational benzo[a]pyrene diol epoxide-DNA adduct types; because of the sensitivity of these methods, they may provide important information necessary for an understanding of the biological effects of the stereochemically distinct BPDE-guanine lesions.

Original languageEnglish (US)
Pages (from-to)281-296
Number of pages16
JournalBiophysical Chemistry
Volume56
Issue number3
DOIs
StatePublished - 1995

Fingerprint

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide
oligonucleotides
Benzo(a)pyrene
Fluorescence Spectrometry
Fluorescence spectroscopy
pyrenes
electrophoresis
Electrophoresis
Oligonucleotides
adducts
Polyacrylamide Gel Electrophoresis
gels
fluorescence
Fluorescence
Temperature
Conformations
spectroscopy
Guanine
Phonons
lesions

Keywords

  • Benzo[a]pyrene
  • BPDE adducts
  • Fluorescence spectroscopy
  • Polyacrylamide gel electrophoresis

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Organic Chemistry
  • Physical and Theoretical Chemistry

Cite this

@article{85479738e7d6486d857912e7db465a1e,
title = "Conformational studies of the (+)-trans, (-)-trans, (+)-cis, and (-)-cis adducts of anti-benzo[a]pyrene diolepoxide to N2-dG in duplex oligonucleotides using polyacrylamide gel electrophoresis and low-temperature fluorescence spectroscopy",
abstract = "Using polyacrylamide gel electrophoresis (PAGE) and low-temperature, laser-induced fluorescence line narrowing (FLN) and non-line narrowing (NLN) spectroscopic methods, the conformational characteristics of stereochemically defined and site-specific adducts derived from the binding of 7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE, a metabolite of the environmental carcinogen benzo[a]pyrene), to DNA were studied. The focus of these studies was on the four stereochemically distinct anti-BPDE modified duplexes 5′-d(CCATCGCTACC) · (GGTAGCGATGG), where G denotes the lesion site derived from trans or cis addition of the exocyclic amino group of guanine to the C10 position of either (+) or (-)-anti-BPDE. PAGE experiments under non-denaturing conditions showed that the (+)-trans adduct causes a significantly greater retardation in the electrophoretic mobility than the other three adducts, probably the result of important adduct-induced distortions of the duplex structure. Low-temperature fluorescence studies in frozen aqueous buffer matrices showed that the (+)-trans adduct adopts primarily an external conformation with only minor interactions with the helix, but a smaller fraction (∼ 25{\%}) appears to exists in a partially base-stacked conformation. The (-)-trans adduct exists almost exclusively (∼ 97{\%}) in an external conformation. Both cis adducts were found to be intercalated; strong electron-phonon coupling observed in their FLN spectra provided additional evidence for significant π-π stacking interactions between the pyrenyl residues and the bases. FLN spectroscopy is shown to be suitable for distinguishing between trans and cis adducts, but lesions with either (+)- or (-)-trans, or (+)- or (-)-cis stereochemical characteristics showed very similar vibrational patterns. Addition of glycerol (50{\%}, v/v) to the matrix caused a partial disruption of the chromophore-base stacking interactions for most adducts, but the (-)-cis isomer showed a strong blue-shift and unusual vibrational frequencies. Low-temperature fluorescence spectroscopy techniques are most suitable for distinguishing between different conformational benzo[a]pyrene diol epoxide-DNA adduct types; because of the sensitivity of these methods, they may provide important information necessary for an understanding of the biological effects of the stereochemically distinct BPDE-guanine lesions.",
keywords = "Benzo[a]pyrene, BPDE adducts, Fluorescence spectroscopy, Polyacrylamide gel electrophoresis",
author = "Myungkoo Suh and Freek Ariese and Small, {Gerald J.} and Ryszard Jankowiak and Liu, {Tong Ming} and Nicholas Geacintov",
year = "1995",
doi = "10.1016/0301-4622(95)00055-3",
language = "English (US)",
volume = "56",
pages = "281--296",
journal = "Biophysical Chemistry",
issn = "0301-4622",
publisher = "Elsevier",
number = "3",

}

TY - JOUR

T1 - Conformational studies of the (+)-trans, (-)-trans, (+)-cis, and (-)-cis adducts of anti-benzo[a]pyrene diolepoxide to N2-dG in duplex oligonucleotides using polyacrylamide gel electrophoresis and low-temperature fluorescence spectroscopy

AU - Suh, Myungkoo

AU - Ariese, Freek

AU - Small, Gerald J.

AU - Jankowiak, Ryszard

AU - Liu, Tong Ming

AU - Geacintov, Nicholas

PY - 1995

Y1 - 1995

N2 - Using polyacrylamide gel electrophoresis (PAGE) and low-temperature, laser-induced fluorescence line narrowing (FLN) and non-line narrowing (NLN) spectroscopic methods, the conformational characteristics of stereochemically defined and site-specific adducts derived from the binding of 7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE, a metabolite of the environmental carcinogen benzo[a]pyrene), to DNA were studied. The focus of these studies was on the four stereochemically distinct anti-BPDE modified duplexes 5′-d(CCATCGCTACC) · (GGTAGCGATGG), where G denotes the lesion site derived from trans or cis addition of the exocyclic amino group of guanine to the C10 position of either (+) or (-)-anti-BPDE. PAGE experiments under non-denaturing conditions showed that the (+)-trans adduct causes a significantly greater retardation in the electrophoretic mobility than the other three adducts, probably the result of important adduct-induced distortions of the duplex structure. Low-temperature fluorescence studies in frozen aqueous buffer matrices showed that the (+)-trans adduct adopts primarily an external conformation with only minor interactions with the helix, but a smaller fraction (∼ 25%) appears to exists in a partially base-stacked conformation. The (-)-trans adduct exists almost exclusively (∼ 97%) in an external conformation. Both cis adducts were found to be intercalated; strong electron-phonon coupling observed in their FLN spectra provided additional evidence for significant π-π stacking interactions between the pyrenyl residues and the bases. FLN spectroscopy is shown to be suitable for distinguishing between trans and cis adducts, but lesions with either (+)- or (-)-trans, or (+)- or (-)-cis stereochemical characteristics showed very similar vibrational patterns. Addition of glycerol (50%, v/v) to the matrix caused a partial disruption of the chromophore-base stacking interactions for most adducts, but the (-)-cis isomer showed a strong blue-shift and unusual vibrational frequencies. Low-temperature fluorescence spectroscopy techniques are most suitable for distinguishing between different conformational benzo[a]pyrene diol epoxide-DNA adduct types; because of the sensitivity of these methods, they may provide important information necessary for an understanding of the biological effects of the stereochemically distinct BPDE-guanine lesions.

AB - Using polyacrylamide gel electrophoresis (PAGE) and low-temperature, laser-induced fluorescence line narrowing (FLN) and non-line narrowing (NLN) spectroscopic methods, the conformational characteristics of stereochemically defined and site-specific adducts derived from the binding of 7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE, a metabolite of the environmental carcinogen benzo[a]pyrene), to DNA were studied. The focus of these studies was on the four stereochemically distinct anti-BPDE modified duplexes 5′-d(CCATCGCTACC) · (GGTAGCGATGG), where G denotes the lesion site derived from trans or cis addition of the exocyclic amino group of guanine to the C10 position of either (+) or (-)-anti-BPDE. PAGE experiments under non-denaturing conditions showed that the (+)-trans adduct causes a significantly greater retardation in the electrophoretic mobility than the other three adducts, probably the result of important adduct-induced distortions of the duplex structure. Low-temperature fluorescence studies in frozen aqueous buffer matrices showed that the (+)-trans adduct adopts primarily an external conformation with only minor interactions with the helix, but a smaller fraction (∼ 25%) appears to exists in a partially base-stacked conformation. The (-)-trans adduct exists almost exclusively (∼ 97%) in an external conformation. Both cis adducts were found to be intercalated; strong electron-phonon coupling observed in their FLN spectra provided additional evidence for significant π-π stacking interactions between the pyrenyl residues and the bases. FLN spectroscopy is shown to be suitable for distinguishing between trans and cis adducts, but lesions with either (+)- or (-)-trans, or (+)- or (-)-cis stereochemical characteristics showed very similar vibrational patterns. Addition of glycerol (50%, v/v) to the matrix caused a partial disruption of the chromophore-base stacking interactions for most adducts, but the (-)-cis isomer showed a strong blue-shift and unusual vibrational frequencies. Low-temperature fluorescence spectroscopy techniques are most suitable for distinguishing between different conformational benzo[a]pyrene diol epoxide-DNA adduct types; because of the sensitivity of these methods, they may provide important information necessary for an understanding of the biological effects of the stereochemically distinct BPDE-guanine lesions.

KW - Benzo[a]pyrene

KW - BPDE adducts

KW - Fluorescence spectroscopy

KW - Polyacrylamide gel electrophoresis

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U2 - 10.1016/0301-4622(95)00055-3

DO - 10.1016/0301-4622(95)00055-3

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EP - 296

JO - Biophysical Chemistry

JF - Biophysical Chemistry

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