Interaction of copper ion with guanosine and related compounds

Tu, Anthony T.; Friederich, Christian G.

doi:10.1021/bi00852a032

Cited by 63 publications

(15 citation statements)

References 12 publications

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“…[21] Although there is some doubt concerning the Cu 2+ -induced enolization of 6-oxopurines, [12,13] changes in IR spectra of Cu 2+ complexes with Ino, Guo, dGuo, GMP, IMP were also interpreted as a result of the shift of the equilibrium towards the enolic form. [25][26][27] It is important to note that the Cu 2+ -induced decrease in the intensity of the carbonyl absorption band in the IR spectra of 6-oxopurines [12,13] may also be caused by a proton transfer of the water molecule of the hydrate ion shell from O h to O6. The transfer of protons along the H-bonds is typical of metal ion complexes with organic molecules of various structures.…”

Section: Coordinating Atoms; Secondary Structurementioning

confidence: 99%

Interaction of divalent metal ions with poly(riboinosinic acid)

Sorokin¹,

Valeev

Degtyar

et al. 2000

Macromol. Chem. Phys.

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Methods of differential UV and visible spectroscopy are used to study the interaction of Mg2+, Ca2+, Mn2+ and Cu2+ ions with four (4×I)‐ and single‐stranded poly I in solutions with 1 mol·l–1 Na+. Up to concentrations of about 0.1 mol·l–1 Mt2+, Mg2+ and Ca2+ ions do not bind to heteroatoms of hypoxanthine of 4×I. Cu2+ ions interact with N7 and/or N1 and possibly with O6 through the water molecule of the hydrate shell of the ion. It is likely that the interaction with O6 causes enolization of the hypoxanthine, N1 deprotonation and, as a result, this leads to the melting of the four‐stranded helix. In single‐stranded chains, Cu2+ ions induce the formation of compact particles which have the effective radii re ≈ 100 Å. The Mn2+‐induced differential spectra are similar to those observed in the presence of Cu2+ ions but in the case of Mn2+ they occur at concentrations about two orders of magnitude higher. In contrast to the positive cooperativity of the Cu2+ binding to bases of single‐stranded poly I, their interaction with 4×I has the negative cooperativity.

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Section: Coordinating Atoms; Secondary Structurementioning

confidence: 99%

Interaction of divalent metal ions with poly(riboinosinic acid)

Sorokin¹,

Valeev

Degtyar

et al. 2000

Macromol. Chem. Phys.

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“…Spectral methods, especially n.m.r., have been favoured hitherto. Unfortunately the interpretation of the results of these studies have not always been unambiguous and the identification of the co-ordination sites has been a subject of disagreement (Tu & Friedrich, 1968;Glassman et al, 1971;Shin et al, 1972;Kotowycz & Suzuki 1973).…”

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confidence: 99%

X-ray evidence for metal–N-7 bonding in a hydrated manganese derivative of guanosine 5′-monophosphate

Meester

Goodgame

Jones

et al. 1974

Biochemical Journal

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Single-crystal X-ray studies of a manganese(II) derivative of guanosine 5′-monophosphate, [Mn(5′-GMP)(H2O)5],3H2O, have shown that it is isostructural with its nickel analogue. The manganese atom therefore is bonded to five water molecules with the remaining octahedral co-ordination site being occupied by N-7 of the nucleotide base. No direct metal–phosphate bonding is involved, but there are structure-stabilizing intramolecular hydrogen bonds between two phosphate oxygen atoms and co-ordinated water molecules.

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“…5) are consistent with this type of mechanism. Caffeine does not appear to be capable of metal chelation (21). However, in view of the large effects exhibited by caffeine in most experiments, the major effects of methylxanthines are not likely to be asociated with the metal-binding capacities of these compounds.…”

Section: Discussionmentioning

confidence: 85%

Increased spore yields of Clostridium perfringens in the presence of methylxanthines

Sacks¹,

Thompson²

1977

Appl Environ Microbiol

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The methylxanthines caffeine, theophylline, and isobutylmethylxanthine greatly increased spore yields of Clostridium perfringens strains FD-1, PS52, and PS49 when grown on Duncan-Strong medium or on a new casein-digest medium. Four other strains (KA3, and National Collection of Type Cultures strains 8798, 8238, and 10240) failed to show any significant increase when tested under similar conditions. The degree of sporulation increase was influenced by the carbohydrate energy source in some strains but not in others. Strain PS52 showed a large increase in spore yield when dextrin was the energy source but only a slight increase when raffinose served as the energy source. Strain FD-1 showed similar increases in spore yield with either dextrin or raffinose. The difficulty commonly associated with inducing sporulation of Clostridium perfringens on laboratory media (22) has impeded studies on the spores of this important organism for many years. The most commonly employed sporulation medium for C. perfringens is probably that of Duncan and Strong (6). Although satisfactory spore yields (>107/ml) have been obtained on this medium with some strains, many strains sporulate only to a very limited extent on it. Ellner's medium (7) and caseindigest media (10) have also been used (3, 4, 8, 9, *15; H. Riemann, Ph.D. thesis, University of Copenhagen, Denmark, 1963), but none are consistently satisfactory (22). Recently we reported that methylxanthines could greatly increase spore yields of strain PS49 in a defined medium and in a new caseindigest medium (14). In the present report, we show that strains PS52 and FD-1 also exhibited large increases in spore yield when methylxanthines were incorporated with the casein-digest medium. Strains PS49, PS52, and FD-1 also demonstrated very significant increases in spore yield when methylxanthines were added to Duncan-Strong (DS) medium. Four other strains showed no increase in spore yield when tested under similar conditions. MATERIALS AND METHODS Medium. The basal medium (CPS) contained Casitone (Difco) (6%), K2HPO4 (0.1%), ethylenediaminetetraacetic acid, ferric salt (0.02%) (11), and

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Interaction of copper ion with guanosine and related compounds

Cited by 63 publications

References 12 publications

Interaction of divalent metal ions with poly(riboinosinic acid)

Interaction of divalent metal ions with poly(riboinosinic acid)

X-ray evidence for metal–N-7 bonding in a hydrated manganese derivative of guanosine 5′-monophosphate

Increased spore yields of Clostridium perfringens in the presence of methylxanthines

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