DNA adducts of the enantiomers of the Pt(II) complexes of the ahaz ligand (ahaz = 3-aminohexahydroazepine) and recognition of these adducts by HMG domain proteins

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Abstract

The bending, unwinding, and structural changes in DNA caused by the binding of each of the enantiomers of the platinum(II) complexes of the ahaz ligand (R- and S-[PtCl2(ahaz)], ahaz = 3-aminohexahydroazepine) have been studied using 20–23 bp oligonucleotides containing TGGT and CGGA-binding sites as has the recognition of the adducts by HMG domain proteins. The domain A of HMGB1 (HMGB1a protein) binds to the adduct formed by the R enantiomer at the CGGA sequence with a similar high affinity as it does to the adduct of antitumor cisplatin, and to the adduct formed by the S enantiomer with a slightly lower affinity. In contrast, HMGB1a binds much more weakly to the ahaz adducts than to the cisplatin adducts formed at the TGGT sequence, with the binding to the adduct formed by the R enantiomer being weakest. Each enantiomer and cisplatin cause unwinding of both sequences that is in the narrow range, 19–22°. There are modest but significant differences in the degree of bending induced, with the S enantiomer causing the least bending, cisplatin intermediate, and the R enantiomer the most. Molecular modeling of the {Pt(ahaz)}/GG adducts in 8-bp models reveals significant differences in the local distortion at the GG-binding sites depending on the flanking bases and shows that interactions between the thymine methyl groups and the ahaz ligand are likely to inhibit bending of the TGGT sequence.

Section snippets

Methods

Materials. [PtCl2(R-ahaz)] and [PtCl2(S-ahaz)] were prepared and characterized as described previously [9]. Cisplatin was obtained from Sigma (Prague, Czech Republic). The stock solutions of platinum compounds were prepared at the concentration of 5 × 10−4 M in 10 mM NaClO4 and stored at 4 °C in the dark. The synthetic oligodeoxyribonucleotides were synthesized and purified as described previously [10]. The duplexes (for their sequences, see Fig. 2, Fig. 3 and the text) uniquely and

Recognition by HMGB1 proteins

An important feature of the mechanism of action of cisplatin is that the major adducts of this platinum drug [1,2-GG intrastrand cross-links (CLs)] are recognized by proteins containing HMG domains [23], [24], [25]. Importantly, DNA modified by transplatin or monodentate platinum(II) compounds, such as [PtCl(dien)]+ (dien = N-(2-aminoethyl)ethane-1,2-diamine) or [PtCl(NH3)3]+, is not recognized by these cellular proteins [26]. It has been shown [23], [27] that the binding of these proteins to DNA

Discussion

As shown for the 1,2-GG intrastrand CL of cisplatin [32], [42], [43] HMGB1a binds to DNA around the site of this adduct in the minor groove while the amine ligands coordinated to platinum reside in the major groove. It is therefore unlikely that the different affinity of HMGB1a to the 1,2-GG intrastrand CLs of [PtCl2(R-ahaz)] and [PtCl2(S-ahaz)] formed in the CGGA sequence is due to different direct interactions of the enantiomeric non-leaving ligands with the protein. The affinity of the

Acknowledgments

This research was supported by the Grant Agency of the Czech Republic (Grant 305/05/2030), the Grant Agency of the Academy of Sciences of the Czech Republic (Grants A5004101 and S5004107). The authors also acknowledge that this work was also carried out within the Institutional Research Plan AVOZ50040507 “Biophysics of dynamic structures and functions of biological systems.”

References (43)

  • G.L. Cohen et al.

    Binding of cis and trans dichlorodiammineplatinum(II) to DNA: evidence for unwinding and shortening of the double helix

    Science

    (1979)
  • G.L. Cohen et al.

    Sequence dependent binding of cis-dichlorodiammineplatinum(II) to DNA

    J. Am. Chem. Soc.

    (1980)
  • N.P. Johnson et al.

    Metal antitumor compounds: the mechanism of action of platinum complexes

    Prog. Clin. Biochem. Med.

    (1989)
  • N. Farrell

    Current status of structure–activity relationships of platinum anticancer drugs: activation of the trans geometry

  • T.W. Hambley

    Platinum binding to DNA: structural controls and consequences

    J. Chem. Soc., Dalton Trans.

    (2001)
  • K. Vickery et al.

    Preparation, characterization, cytotoxicity, and mutagenicity of a pair of enantiomeric platinum(II) complexes with the potential to bind enantioselectively to DNA

    J. Med. Chem.

    (1993)
  • V. Brabec et al.

    Sequence-dependent distortions induced in DNA by monofunctional platinum(II) binding

    Biochemistry

    (1992)
  • J. Kasparkova et al.

    Site-specific d(GpG) intrastrand cross-links formed by dinuclear platinum complexes. Bending and NMR studies

    Biochemistry

    (1996)
  • K. Stehlikova et al.

    DNA bending and unwinding due to the major 1,2-GG intrastrand cross-link formed by antitumor cis-diamminedichloroplatinum(II) are flanking-base independent

    Nucleic Acids Res.

    (2002)
  • Q. He et al.

    Intercalating residues determine the mode of HMG1 domains A and B binding to cisplatin-modified DNA

    Biochemistry

    (2000)
  • J. Kasparkova et al.

    Effect of geometric isomerism in dinuclear platinum antitumor complexes on DNA interstrand cross-linking

    Biochemistry

    (1999)
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