Base-specific and enantioselective studies for the DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and dipyrido[3,2-a: 2′,3′-c]phenazine

Mudasir, Karna Wijaya, Endang Tri Wahyuni, Hidenari Inoue, Naoki Yoshioka

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Base specificity and enantioselectivity for the DNA binding of [Fe(phen)2(dppz)]2+ (phen = 1,10-phenanthroline and dppz = dipyrido[3,2-a:2′,3′-c]phenazine) have been studied by determining the equilibrium binding constant (Kb) of the iron(II) complex to calf thymus DNA (ct-DNA), poly[(dA-dT)2], poly[(dG-dC)2] and poly[(dI-dC)2] using spectrophotometric titration and by monitoring the CD spectral profile of the iron(II) complex in the presence and absence of different types of DNA using circular dichroism (CD) spectroscopy, respectively. It has been shown that [Fe(phen)2(dppz)]2+ prefers to intercalate into the A-T and I-C sequences of poly[(dA-dT)2] and poly[(dI-dC)2] rather than into the G-C sequences of poly[(dG-dC)2] or into the base pairs of ct-DNA. In contrast to previous reports, it is a surprising observation that the enantioselectivity of the DNA binding for [Fe(phen)2(dppz)]2+ is base-dependent in nature. The Δ-enantiomer of [Fe(phen)2(dppz)]2+ is preferentially intercalated into the base pairs of poly[(dG-dC)2] or ct-DNA as indicated by its CD spectral profiles. On the other hand, the Λ-enantiomer of [Fe(phen)2(dppz)]2+ is favorably intercalated into poly[(dA-dT)2] or poly[(dI-dC)2] as suggested by the opposite CD spectral profile. This preferential binding of Λ-[Fe(phen)2(dppz)]2+ for the A-T sequence may be attributed to the fact that the binding site for the A-T sequence is relatively facile and thus the steric effect caused by the ancillary (non-intercalated) phen ligands is alleviated. The degree of enantioselectivity represented by inversion constants (Kinv) decreases as the salt concentration in the solution increases, indicating that electrostatic interaction is also operating in the ct-DNA-binding events of the iron (II) complex.

Original languageEnglish
Pages (from-to)163-170
Number of pages8
JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Volume66
Issue number1
DOIs
Publication statusPublished - 2007 Jan

Fingerprint

Enantioselectivity
Dichroism
DNA
Iron
deoxyribonucleic acid
Ligands
Thymus
calves
iron
ligands
Enantiomers
dichroism
Poly dA-dT
Circular dichroism spectroscopy
enantiomers
Coulomb interactions
Titration
profiles
Salts
Binding Sites

Keywords

  • 1,10-Phenanthroline
  • Base-specificity
  • DNA-binding
  • dppz
  • Enantioselectivity
  • Iron(II)

ASJC Scopus subject areas

  • Spectroscopy

Cite this

@article{b55ad44cba6040d3ad8be2682cab9307,
title = "Base-specific and enantioselective studies for the DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and dipyrido[3,2-a: 2′,3′-c]phenazine",
abstract = "Base specificity and enantioselectivity for the DNA binding of [Fe(phen)2(dppz)]2+ (phen = 1,10-phenanthroline and dppz = dipyrido[3,2-a:2′,3′-c]phenazine) have been studied by determining the equilibrium binding constant (Kb) of the iron(II) complex to calf thymus DNA (ct-DNA), poly[(dA-dT)2], poly[(dG-dC)2] and poly[(dI-dC)2] using spectrophotometric titration and by monitoring the CD spectral profile of the iron(II) complex in the presence and absence of different types of DNA using circular dichroism (CD) spectroscopy, respectively. It has been shown that [Fe(phen)2(dppz)]2+ prefers to intercalate into the A-T and I-C sequences of poly[(dA-dT)2] and poly[(dI-dC)2] rather than into the G-C sequences of poly[(dG-dC)2] or into the base pairs of ct-DNA. In contrast to previous reports, it is a surprising observation that the enantioselectivity of the DNA binding for [Fe(phen)2(dppz)]2+ is base-dependent in nature. The Δ-enantiomer of [Fe(phen)2(dppz)]2+ is preferentially intercalated into the base pairs of poly[(dG-dC)2] or ct-DNA as indicated by its CD spectral profiles. On the other hand, the Λ-enantiomer of [Fe(phen)2(dppz)]2+ is favorably intercalated into poly[(dA-dT)2] or poly[(dI-dC)2] as suggested by the opposite CD spectral profile. This preferential binding of Λ-[Fe(phen)2(dppz)]2+ for the A-T sequence may be attributed to the fact that the binding site for the A-T sequence is relatively facile and thus the steric effect caused by the ancillary (non-intercalated) phen ligands is alleviated. The degree of enantioselectivity represented by inversion constants (Kinv) decreases as the salt concentration in the solution increases, indicating that electrostatic interaction is also operating in the ct-DNA-binding events of the iron (II) complex.",
keywords = "1,10-Phenanthroline, Base-specificity, DNA-binding, dppz, Enantioselectivity, Iron(II)",
author = "Mudasir and Karna Wijaya and Wahyuni, {Endang Tri} and Hidenari Inoue and Naoki Yoshioka",
year = "2007",
month = "1",
doi = "10.1016/j.saa.2006.02.037",
language = "English",
volume = "66",
pages = "163--170",
journal = "Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy",
issn = "1386-1425",
publisher = "Elsevier",
number = "1",

}

TY - JOUR

T1 - Base-specific and enantioselective studies for the DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and dipyrido[3,2-a

T2 - 2′,3′-c]phenazine

AU - Mudasir,

AU - Wijaya, Karna

AU - Wahyuni, Endang Tri

AU - Inoue, Hidenari

AU - Yoshioka, Naoki

PY - 2007/1

Y1 - 2007/1

N2 - Base specificity and enantioselectivity for the DNA binding of [Fe(phen)2(dppz)]2+ (phen = 1,10-phenanthroline and dppz = dipyrido[3,2-a:2′,3′-c]phenazine) have been studied by determining the equilibrium binding constant (Kb) of the iron(II) complex to calf thymus DNA (ct-DNA), poly[(dA-dT)2], poly[(dG-dC)2] and poly[(dI-dC)2] using spectrophotometric titration and by monitoring the CD spectral profile of the iron(II) complex in the presence and absence of different types of DNA using circular dichroism (CD) spectroscopy, respectively. It has been shown that [Fe(phen)2(dppz)]2+ prefers to intercalate into the A-T and I-C sequences of poly[(dA-dT)2] and poly[(dI-dC)2] rather than into the G-C sequences of poly[(dG-dC)2] or into the base pairs of ct-DNA. In contrast to previous reports, it is a surprising observation that the enantioselectivity of the DNA binding for [Fe(phen)2(dppz)]2+ is base-dependent in nature. The Δ-enantiomer of [Fe(phen)2(dppz)]2+ is preferentially intercalated into the base pairs of poly[(dG-dC)2] or ct-DNA as indicated by its CD spectral profiles. On the other hand, the Λ-enantiomer of [Fe(phen)2(dppz)]2+ is favorably intercalated into poly[(dA-dT)2] or poly[(dI-dC)2] as suggested by the opposite CD spectral profile. This preferential binding of Λ-[Fe(phen)2(dppz)]2+ for the A-T sequence may be attributed to the fact that the binding site for the A-T sequence is relatively facile and thus the steric effect caused by the ancillary (non-intercalated) phen ligands is alleviated. The degree of enantioselectivity represented by inversion constants (Kinv) decreases as the salt concentration in the solution increases, indicating that electrostatic interaction is also operating in the ct-DNA-binding events of the iron (II) complex.

AB - Base specificity and enantioselectivity for the DNA binding of [Fe(phen)2(dppz)]2+ (phen = 1,10-phenanthroline and dppz = dipyrido[3,2-a:2′,3′-c]phenazine) have been studied by determining the equilibrium binding constant (Kb) of the iron(II) complex to calf thymus DNA (ct-DNA), poly[(dA-dT)2], poly[(dG-dC)2] and poly[(dI-dC)2] using spectrophotometric titration and by monitoring the CD spectral profile of the iron(II) complex in the presence and absence of different types of DNA using circular dichroism (CD) spectroscopy, respectively. It has been shown that [Fe(phen)2(dppz)]2+ prefers to intercalate into the A-T and I-C sequences of poly[(dA-dT)2] and poly[(dI-dC)2] rather than into the G-C sequences of poly[(dG-dC)2] or into the base pairs of ct-DNA. In contrast to previous reports, it is a surprising observation that the enantioselectivity of the DNA binding for [Fe(phen)2(dppz)]2+ is base-dependent in nature. The Δ-enantiomer of [Fe(phen)2(dppz)]2+ is preferentially intercalated into the base pairs of poly[(dG-dC)2] or ct-DNA as indicated by its CD spectral profiles. On the other hand, the Λ-enantiomer of [Fe(phen)2(dppz)]2+ is favorably intercalated into poly[(dA-dT)2] or poly[(dI-dC)2] as suggested by the opposite CD spectral profile. This preferential binding of Λ-[Fe(phen)2(dppz)]2+ for the A-T sequence may be attributed to the fact that the binding site for the A-T sequence is relatively facile and thus the steric effect caused by the ancillary (non-intercalated) phen ligands is alleviated. The degree of enantioselectivity represented by inversion constants (Kinv) decreases as the salt concentration in the solution increases, indicating that electrostatic interaction is also operating in the ct-DNA-binding events of the iron (II) complex.

KW - 1,10-Phenanthroline

KW - Base-specificity

KW - DNA-binding

KW - dppz

KW - Enantioselectivity

KW - Iron(II)

UR - http://www.scopus.com/inward/record.url?scp=33751547881&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33751547881&partnerID=8YFLogxK

U2 - 10.1016/j.saa.2006.02.037

DO - 10.1016/j.saa.2006.02.037

M3 - Article

C2 - 16822711

AN - SCOPUS:33751547881

VL - 66

SP - 163

EP - 170

JO - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

JF - Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

SN - 1386-1425

IS - 1

ER -