A Fourier transform infrared study of the electrophilic attack at the N<sub>7</sub>-site of guanosine-5′-monophosphate

Tajmir-Riahi, H.A.; Théophanides, T.

doi:10.1139/v84-044

Cited by 32 publications

(20 citation statements)

References 19 publications

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“…The ability of Ag(I) to promote the Z structure in poly(dG-dG) is presently under study. Some of our spectroscopic interpretations are supported by a recent study of complexes of nucleotides with metal ions (21 ). These samples were crystals and did not include Hg(II) so that considerable care is required in drawing conclusions which apply to our data.…”

Section: Discussionsupporting

confidence: 53%

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

Keller¹,

Hartman²

1987

Journal of Biomolecular Structure and Dynamics

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Infrared spectroscopy was used to study hydrated double-helical poly(dG-dC) complexed with varying amounts of mercury(II). For one Hg(II) per ten nucleotide residues (r = 0.1), the B structure was stabilized and the B* structure was absent at high hydration. The Z structure did not form as hydration was reduced. For r = 0.2, the B and Z structures coexisted at high hydration and the transition to total Z structure was broad as hydration was reduced. Hg(II) was bound exclusively to the guanine residues probably at N3 or N7 for r less than or equal to 0.25. The cytosine residue did not protonate (at N3) as Hg(II) was bound to guanine. The addition of NaCl together with Hg(II) reduced the binding of Hg(II), stabilized the B structure at the highest hydration and caused a sharp transition between the B and Z structures as hydration was lowered. Hydration with D2O stabilized the Z structure for poly(dG-dC) complexed with HgCl2.

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Section: Discussionsupporting

confidence: 53%

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

Keller¹,

Hartman²

1987

Journal of Biomolecular Structure and Dynamics

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“…The ir frequencies of the uncomplexed DNA and its proton complexes at pH 7-2 are given in Table I. The difference spectra of calf thymus DNA in the presence of HCl and copper cation contain several positive and negative derivative features, in the region of 1800-600 cm-' , that are arising from intensity CU2jDNAIPl ratios FIGURE 4 The intensity variations of several DNA in-plane vibrations (cm-' ) as a function ofcopper cation concentrations [different CuZ+/DNA( P) molar ratios]. …”

Section: Resultsmentioning

confidence: 99%

The effect of HCl on the solution structure of calf thymus DNA: A comparative study of DNA denaturation by proton and metal cations using fourier transform IR difference spectroscopy

et al. 1995

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The interaction of HCl with calf thymus DNA was investigated in aqueous solution at pH 7-2 with H+/DNA(P) (P:phosphate) molar ratios (r) of 1/80, 1/40, 1/20, 1/10, 1/4, 1/2, and 1, using Fourier Transform (FTIR) difference spectroscopy. Correlations between spectral changes, proton binding mode, DNA denaturation, and conformational variations are established. A comparison was also made between the ir spectra of denaturated DNA, in the presence of proton and Cu ions with similar cation concentrations. The FTIR difference spectroscopic results have shown that at low proton concentrations of r = 1/80 and 1/40 (pH 7-5), no major spectral changes occur for DNA, and the presence of H+ results in an increased base-stacking interaction and helical stability. At higher proton concentrations of r > 1/40, the proton binding to the cytosine and adenine bases begins with major destabilization of the helical duplex. As base protonation progresses, a B to C conformational conversion occurs with major DNA spectral changes. Protonation of guanine bases occurs at a high cation concentration r > 1/2 (pH < 3) with a major increase in the intensity of several DNA in-plane vibrations. Copper ion complexation with DNA exhibits marked similarities with proton at high cation concentrations (r > 1/10), whereas at low metal ion concentrations, copper-PO2 and copper-guanine N-7 bindings are predominant. No major DNA conformational transition was observed on copper ion complexation.

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“…However, d ‐glucurono‐6,3‐lactone can yield an NMR spectrum which partially resembles the one for polyglucuronic acids. Knowing that the β form of d ‐glucurono‐6,3‐lactone is predominant in aqueous solution, we compared its C NMR spectrum with ours. Close likeness was found between our spectrum for the β free anomer of glucuronic acid (Fig.…”

Section: Resultsmentioning

confidence: 99%

Supramolecular structure and anomer‐selective formation of polyglucuronic acid

Stetco

2012

Polymer International

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Polyglucuronic acids provide a biocompatible matrix for industries ranging from pharmaceuticals to agriculture. Here we provide a method for selectively producing α‐polyglucuronic acid, a simple alternative to the oxidation of cellulose or amylose with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl radical (TEMPO) or isolation from bacterial cultures. Atomic force micrographs show the pH‐dependent formation and persistence of polyglucuronic acid fibrils, while NMR studies demonstrate the selectivity of the glycosidic linkage. By controlling pH, oligoglucuronate chains are created, with both NMR and AFM data showing the preservation of this linkage in basic medium after formation under acid. Clear evidence for the formation of the C–O–C glycosidic bond comes from peaks in the 13C NMR spectra, revealing a linkage through the anomeric carbon atom and also a linkage with a ring carbon atom.

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

Cited by 32 publications

References 19 publications

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

The effect of HCl on the solution structure of calf thymus DNA: A comparative study of DNA denaturation by proton and metal cations using fourier transform IR difference spectroscopy

Supramolecular structure and anomer‐selective formation of polyglucuronic acid

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

Cited by 32 publications

References 19 publications

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

Structural Forms and Transitions for the Complex of Mercury(II) with Poly(dG-dC)

The effect of HCl on the solution structure of calf thymus DNA: A comparative study of DNA denaturation by proton and metal cations using fourier transform IR difference spectroscopy

Supramolecular structure and anomer‐selective formation of polyglucuronic acid

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