Nucleic acid constituents

These compounds have been extensively investigated because they are important nucleic acid constituents. Uracil has been shown conclusively to exist predominantly as pyrimidine-2,4-dione (99) both by a refined X-ray crystallographic technique in which the positions... 

Nucleotide (Section 28. ) A nucleic acid constituent, consisting of a sugar residue bonded both to a heterocyclic purine or pyrimidine base and to a phosphoric acid. 

The stereochemistry of metal complexes of nucleic acid constituents. D. J. Hodgson, Prog. Inorg. Chem., 1977, 23,211-254 (175). 

Stereoselectivity in the binding of transition metal chelate complexes to nucleic acid constituents bonding and non-bonding effects. L. G. Marzilli and T. J. Kistenmacher, Acc. Chem. Res., 1977, 10,146-152 (29). 

According to Barbieri et al., it can not be excluded that some of the coordination sites are occupied by (Nj atoms of the nucleic acid constituents. The precipitate obtained from [Ph2Sn(IV)] would contain both the [R2Sn(IV)] -DNA complex and distannoxane [(Ph2SnCl)20]. The main products of the... 

Burtis, C. A. and Gere, D. R. "Nucleic Acid Constituents by Liquid Chromatography", Varian Aerograph, California, 1970. 

Willems, A. V., Deforce, D. L., Van Peteghem, C. H., and Van Bocxlaer, J. E. (2005). Analysis of nucleic acid constituents by on-line capillary electrophoresis-mass spectrometry. Electrophoresis 26, 1221-1253. 

WHO (1993) Guidelines for Drinking Water Quality, 2nd Ed., Vol. 1. Recommendations, Geneva Wilmer, J.W.G.M. Natarajan, A.T. (1981) Induction of sister-chromatid exchanges and chromosome aberrations by y-irradiated nucleic acid constituents in CHO cells. Mutat. Res., 88,... 

Little is known about the chemistry of silver(I) complexes of unsubstituted pyrimidine however, an extensive range of substituted pyrimidine complexes have been investigated due to their use in the preparation of nucleic acid constituents.85 94 In these reactions, which lead to the formation of glycosides, silver salts of uracils or thymines are treated with poly-0-... 

Leonov D, Elad D (1974a) Ultraviolet-and y-ray-induced reactions of nucleic acid constituents. Reactions of purines with ethers and dioxolane. J Org Chem 39 1470-1473 Leonov D, Elad D (1974b) Photochemical and y-ray-induced reactions of nucleic acid constituents. Suppression of the reactivity of pyrimidines in the presence of purines. J Am Chem Soc 96 5635-5637... 

Leonov D, Salomon J, Sasson S, Elad D (1973) Ultraviolet- and y-ray-induced reactions of nucleic acid constituents with alcohols. On the selectivity of these reactions for purines. Photochem Photobiol 17 465-468... 

Yamamoto O (1973) Radiation-induced binding of nucleic acid constituents with protein constituents and with each other. Int J Radiat Phys Chem 5 213-229 Yamamoto O, Mandal PC (1988) Radiation-induced fluorescence changes of 2 -deoxycytidine and cytidilyl-cytidine in aqueous solution. Comparison with radiolytic behaviors of other nudeo-base derivatives. J Radiat Res 131-143... 

Computational Studies on Platinum Antitumor Complexes and Their Adducts with Nucleic-Acid Constituents... 

The aim of the present review is (1) to outline the experimental techniques used to explore the primary radiation induced defects in nucleic acid constituents in the solid-state, (2) to provided an updated review of what is currently known about these primary induced radiation defects in DNA, (3) to consider the transformations the primary radicals undergo in order to look at biologically relevant lesion such as strand breaks, (4) to see how theoretical calculations are currently being used to assist in making free radical assignments, and finally, (5) to look at unsolved problems and make suggestions for future work. 

Three-center hydrogen bonds in the nucleic acid constituents occur as frequently as in the carbohydrates (see Thble 2.3). Because there are virtually no neutron diffraction studies available for this class of compounds, the analysis of the three-center bonds has to rely on data where the X-H bond lengths are normalized and are therefore to some extent less reliable than those of the carbohydrates (Table 8.3) which are based on neutron diffraction data. 

The survey on nucleic acid constituents nevertheless suggests that... 

Since nucleic acid constituents exhibit a wider range of donor and acceptor types, the three-center hydrogen bonds have more variation than in+the carbohydrates. It is clear from the data summarized in Thble 8.5 that - NH3 (and NH4), O—H and — NH2 groups tend to form more three-center bonds than OwH... 

The three-center hydrogen bonds observed in the crystal structures of the amino acids are described in Thble 8.6. They range from symmetrical to unsymmet-rical, as found for the carbohydrates and nucleic acid constituents, but there is a significantly greater tendency to form more unsymmetrical bonds. A particular feature are the chelated three-center hydrogen bonds discussed below. 

Chelated three-center hydrogen bonds and chelated bifurcated hydrogen bonds involve two acceptors or two donors belonging to the same molecule. They are observed in the crystal structures of the amino acids and their salts (Thble 8.7), and in the crystal structures of the nucleic acid constituents (Thble 8.8) ... 

In the nucleic acid constituents, the donors in the chelated three-center hydrogen bonds show a much greater variety with several types of charged and un-... 

Configurations involving simultaneously three-center and bifurcated hydrogen bonds are observed in the crystal structures of nucleic acid constituents purines, pyrimidines, nucleosides, nucleotides. 

Chloride ions are three- and four-coordinated. The neutron diffraction analyses of the amino acid hydrochlorides provided the data in Thble 11.1, and the more extensive data obtained from the X-ray analyses of hydrochlorides of nucleic acid constituents are given in Thble 11.2. The data indicate clearly that the chloride ion may be three- or four-coordinated. When three-coordinated, the bonds may be in planar or in pyramidal configuration, with no bimodal distribution. The ligands of four-coordinated chloride ions are only very approximately in tetrahedral con-... 

Theoretically, the purine- and pyrimidine-based nucleic acid constituents and the barbiturates have the potential to occur in several tautomeric forms of the keto/ enol and amino/imino type where the aromatic character of the six-membered pyrimidine ring is fully or, as in the barbiturates, partially retained, as illustrated in Fig. 15.4. In these molecular species, which are all feasible on the basis of organic chemical considerations, the hydrogen-bonding donor/acceptor properties of the functional amino, imino, enol and keto groups vary considerably, being donor in one form and acceptor in the other. 

Szczepaniak K, Szczepaniak M (1987) Matrix isolation infrared studies of nucleic acid constituents. J Mol Struct 156 29-42... 

Beveridge DL, Maye PV, Jayaram B, Ravishanker G, Mezei M (1984) Aqueous hydration of nucleic acid constituents Monte Carlo computer simulation studies. J Biomol Struct Dynam 2 261-270... 

Horvath, C., High-Performance Ion-Exchange Chromatography with Narrow-Bore Columns Rapid Analysis of Nucleic Acid Constituents at... 

Analysis of Nucleic Acid Constituents at the Subnanomede Level (Horvath). 21 79... 

Whereas nucleic acid constituents tend to vertically associate in aqueous solutions, the introduction of organic solvents tends to disrupt this associative process, leading to a destacking of the compounds. 

The retention behavior of nucleic acid constituents in the presence of increasing concentrations of an organic modifier is typical of that expected based upon solvophobic mechanisms with increasing concentrations of organic modifier, the capacity for solute retention is decreased. As expected, the use of a stronger eluent under reversed-phase conditions (e.g., acetonitrile vis-a-vis methanol) results in a subsequent decrease in the capacity ratios of all compounds in the chromatographic analysis. 

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