Guanine properties

Another property of pyrimidines and purines is their strong absorbance of ultraviolet (UV) light, which is also a consequence of the aromaticity of their heterocyclic ring structures. Figure 11.8 shows characteristic absorption spectra of several of the common bases of nucleic acids—adenine, uracil, cytosine, and guanine—in their nucleotide forms AMP, UMP, CMP, and GMP (see Section 11.4). This property is particularly useful in quantitative and qualitative analysis of nucleotides and nucleic acids. 

Guanine derivatives, the effects of N(7)-coordinated ci.s-diammine-platinum(II) on the acid-base properties of 98PAC845. 

Conformational properties of DNA strands containing guanine and adenine 98CLY530. 

Our studies showed that i) substitution of an exocyclic amino group of dG is effective in modulating the chemical properties of dG toward one-electron oxidation, and ii) decomposition of the guanine radical cation was effectively suppressed near dphG. These results indicate that dphG is a prototype of nucleosides functioning as an intrinsic antioxidant of duplex DNA toward one-electron oxidation. 

MR Harnden, RL Jarret, MR Boyed, D Sulton, RA Vene Hodge. Prodrugs of the selective antiherpesvirus agent 9-[4-hydroxy-3-(hydroxymethyl) but 1-yl] guanine (BRL 39123) with improved gastrointestinal absorption properties. J Med Chem 32 1738-1743, 1989. 

Initial experiments showed that [0s(ri6-bip)Cl(en)]+ (26) was not cytotoxic towards cancer cells (105), but a later reassessment of the cytotoxic activity of this compound showed that it indeed was active at micromolar concentrations (IC50 values of 7.6 (A2780) and 10 pM (A549)) (112). A possible explanation for the initial lack of activity may be the partial decomposition of the complex in stock test solutions prepared in DMSO, as was evidenced in subsequent studies (112). The cytotoxicity data are now more in line with the chemical properties of the complex, i.e. observed hydrolysis rate and guanine binding. 

These definitions apply to any atomic system, molecule or crystal. Fig. 7.3 a illustrates their application to the charge distribution of the guanine-cytosine base-pair. Fig. 7.3 b shows the molecular structure defined by the bond paths and the associated CPs that clearly and uniquely define the three hydrogen bonds that link the two bases. Fig. 7.3 c shows the atomic boundaries and bond paths overlaid on the electron density in the plane of the nuclei. All properties of the atoms can be determined, enabling one, for example, to determine separately the energy of formation of each of the three hydrogen bonds. 

Nature of the critical cellular adduct. It is to be expected that the properties and behavior of the adduct formed with DNA will be of key importance. For example, the carcinogenicity of vinyl chloride has been attributed to its 7-N-(2-oxoethyl) derivative of guanine [60, 61]. 

Catty, D. J., PadreU, E., Codina, J., Bimbaumer, L., HUdebrandt, J. D., and Iyengar, R. (1990) Distinct guanine nucleotide binding and release properties of the three Gi proteins. J. Biol. Chem. 265,6268-6273. 

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