High resolution nuclear magnetic resonance studies of platinum(II) – guanosine-5′-monophosphate interactions in aqueous solutions

Polissiou, Moschos G.; Viet, Minh Tan Phan; St‐Jacques, M.; Théophanides, T.

doi:10.1139/v81-486

Cited by 16 publications

(5 citation statements)

References 9 publications

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“…Substitution of a large atom such as Br (7) or a bulky organic substance such as 2-(acetylamino)fluorene (carcinogen) (8) at the C-8 position of the guanine moiety or a negative group such as PtCl3 at N 7 could facilitate the B to Z transition. It has been shown that the coordination of metal cations such as the Mg(II) ion (9,10,11), the [Co(NH 3 ) 6 ]+ 3 (11 ,12) and the PtCl3 group (13) to the N 7 -site of the guanine base also can bring about the B to Z transition.…”

Section: Introductionmentioning

confidence: 99%

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

Théophanides

Tajmir-Riahi

1985

Journal of Biomolecular Structure and Dynamics

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The interaction of DNA and RNA with Cu(II), Mg(II), [Co(NH3)6]3+ [Co(NH3)5Cl]2+ chlorides and, cis- and trans-Pt(NH3)2Cl2 (CIS-DDP, trans-DDP) has been studied by Fourier Transform Infrared (FT-IR) spectroscopy and a correlation between metal-base binding and conformational transitions in the sugar pucker has been established. It has been found that RNA did not change from A-form on complexation with metals, whereas DNA exhibited a B to Z transition. The marker bands for the A-form (C3'-endo-anti conformation) were found to be near 810-816 cm-1, while the bands at 825 and 690 cm-1 are marker bands for the B-conformation (C2'-endo, anti). The B to Z (C3'-endo. syn conformation) transition is characterized by the shift of the band at 825 cm-1 to 810-816 cm-1 and the shift of the guanine band at 690 cm-1 to about 600-624 cm-1.

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Section: Introductionmentioning

confidence: 99%

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

Théophanides

Tajmir-Riahi

1985

Journal of Biomolecular Structure and Dynamics

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“…Raman and nmr spectroscopy I has often been used (1,2,(5)(6)(7)(8) to characterize the nature of such electrophilic interaction with mono-and polynucleotides, whereas ir is the least used technique for this purpose, so far (9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

A Fourier transform infrared study of the electrophilic attack at the N₇-site of guanosine-5′-monophosphate

Tajmir-Riahi¹,

Théophanides²

1984

Can. J. Chem.

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Fourier transform infrared spectra of several N7-bound cations of guanosine-5′monophosphate disodium salt (5′-GMPNa2), such as N7-H+GMP, N7-MeGMP, and N7-MGMP, where Me = CH3+ and M = divalent metal ions, Cd, Mn, Co, Ni, Cu, Pt, and Mg, have been recorded and a correlation between the spectral changes and the nature of the electrophile (H+, CH3+, and M2+) bound has been established. Spectroscopic evidence shows that methylation of the N7-position of 5′-GMPNa2 causes larger perturbation on the guanine ring system than protonation or metalation, in the order Me+ > H+ > M2+. The effect of an N7-electrophilic attack on the vibrational frequencies of the purine, the sugar, and the phosphate group is discussed.

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“…This slow equilibrium is characterized by distinct signals for the involved sugar protons, and their relative populations may be calculated only from their signal integrals, resulting in nearly equal percentages. Regarding the gg conformation about the bond C4′–C5′, although a decrease in the gg percentage was expected [ 48 ], it appears to be practically stable for [ 1 -guo] and [ 2 -guo]A, while it is slightly lower for [ 2 -guo]B. In other words, the platination of guo by ( 1 ) and ( 2 ) does not practically affect the conformation around the C4′–C5′ bond compared to free guanosine.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the [2-guo]B adopts a more pronounced tendency for anti-conformation (93%), which may induce greater distortion in the DNA helix. a,b Taken from reference [48] and [36], respectively.…”

Section: Sugar Conformation Analysismentioning

confidence: 99%

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The Influence of the Auxiliary Ligand in Monofunctional Pt(II) Anticancer Complexes on the DNA Backbone

Tagari,

Sifnaiou,

Tsolis

et al. 2024

IJMS

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Monofunctional platinum complexes offer a promising alternative to cisplatin in cancer chemotherapy, showing a unique mechanism of action. Their ability to induce minor helix distortions effectively inhibits DNA transcription. In our study, we synthesized and characterized three monofunctional Pt(II) complexes with the general formula [Pt(en)(L)Cl]NO3, where en = ethylenediamine, and L = pyridine (py), 2-methylpyridine (2-mepy), and 2-phenylpyridine (2-phpy). The hydrolysis rates of [Pt(en)(py)Cl]NO3 (1) and [Pt(en)(2-mepy)Cl]NO3 (2) decrease with the bulkiness of the auxiliary ligand with k(1) = 2.28 ± 0.15 × 10−4 s−1 and k(2) = 8.69 ± 0.98 × 10−5 s−1 at 298 K. The complex [Pt(en)(2-phpy)Cl]Cl (3) demonstrated distinct behavior. Upon hydrolysis, an equilibrium (Keq = 0.385 mM) between the complexes [Pt(en)(2-phpy)Cl]+ and [Pt(en)(2-phpy-H+)]+ was observed with no evidence (NMR or HR-ESI-MS) for the presence of the aquated complex [Pt(en)(2-phpy)(H2O)]2+. Despite the kinetic similarities between phenanthriplatin and (2), complexes (1) and (2) exhibit minimal activity against A549 lung cancer cell line (IC50 > 100 μΜ), whereas complex (3) exhibits notable cytotoxicity (IC50 = 41.11 ± 2.1 μΜ). In examining the DNA binding of (1) and (2) to the DNA model guanosine (guo), we validated their binding through guoN7, which led to an increased population of the C3′-endo sugar conformation, as expected. However, we observed that the rapid transition 2E (C2′-endo) ↔ 3E (C3′-endo), in the case of [Pt(en)(py)(guo)](NO3)2 ([1-guo]), slows down in the case of [Pt(en)(2-mepy)(guo)](NO3)2 ([2-guo]), resulting in separate signals for the two conformers in the 1H NMR spectra. This phenomenon arises from the steric hindrance between the methyl group of pyridine and the sugar moiety of guanosine. Notably, this hindrance is absent in [2-(9-MeG)] (9-MeG = 9-methylguanine), probably due to the absence of a bulky sugar unit in 9-MeG. In the case of (3), where the bulkiness of the substitution on the pyridine is further increased by a phenyl group, we observed a notable proximity between 9-MeGH8 and the phenyl ring of 2-phpy. Considering that only (3) exhibited good cytotoxicity against the A549 cancer cell line, it is suggested that auxiliary ligands, L, with an extended aromatic system and proper orientation in complexes of the type cis-[Pt(en)(L)Cl]NO3, may enhance the cytotoxic activity of such complexes.

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High resolution nuclear magnetic resonance studies of platinum(II) – guanosine-5′-monophosphate interactions in aqueous solutions

Cited by 16 publications

References 9 publications

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

A Fourier transform infrared study of the electrophilic attack at the N₇-site of guanosine-5′-monophosphate

The Influence of the Auxiliary Ligand in Monofunctional Pt(II) Anticancer Complexes on the DNA Backbone

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High resolution nuclear magnetic resonance studies of platinum(II) – guanosine-5′-monophosphate interactions in aqueous solutions

Cited by 16 publications

References 9 publications

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

Flexibility of DNA and RNA upon Binding to Different Metal Cations. An Investigation of the B to A to Z Conformational Transition by Fourier Transform Infrared Spectroscopy

A Fourier transform infrared study of the electrophilic attack at the N7-site of guanosine-5′-monophosphate

The Influence of the Auxiliary Ligand in Monofunctional Pt(II) Anticancer Complexes on the DNA Backbone

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A Fourier transform infrared study of the electrophilic attack at the N₇-site of guanosine-5′-monophosphate