Adenine cytosine

Many protective groups have been developed for the amino group, including carbamates (>NCO,R), used for the protection of ammo acids in peptide and protein syntheses, and amides (>NCOR). used more widely in syntheses of alkaloids and for the protection of the nitrogen bases adenine, cytosine, and guanine in nucleo-... 

Kinoshita, Imoto etal.11 14) synthesized other anionic models, 5 (APVP), CPVP, UPVP, TPVA, HPVA, THPVA, and 6 (AMPPVA), by the polymer reaction of N-eoupled(2-dihydrogenphosphate)-ethylderivatives of nucleic acid bases (or adenosine-5 -phosphate, AMP) with polyvinylaleohol. A, C, U, T, H, and TH denote adenine, cytosine, uracil, thymin, hypoxanthine, and theophylline, respectively. The authors reported the apparent hypochromities of 3 to 16% for many kinds of mixtures of the models and DNA or RNA, as compiled in Table 1. However, for the mixtures APVA + RNA, HPVA + RNA HPVA + DNA, THPVA + RNA, CPVA + DNA and CPVA + RNA, no hypochromicity was detected. 

Since nucleic acids and enzymes play such a large role in chromosome replication during mitosis, a considerable amount of research has been conducted in this area to control viruses. On the molecular level, analogues of nucleic acids are capable of forming complexes with adenine, cytosine, uracil, thymine, and guanine. Through complexation, these nucleic acid analogues are potential inhibitors of biosyntheses that require nucleic acids as templates. 

In different molecules of DNA the four nitrogenous bases (adenine, cytosine, guanine, and thymine) appear in different order, and the genetic... 

Deoxyribose nucleic acid (DNA) Comprises a backbone with four nucleotide bases, adenine, cytosine, guanine and thymine, bound to it. The genetic information in all cells is encoded in this genome of double-stranded DNA, comprising 3 billion base pairs located in the chromosomes. 

Florian, J. Goodman, M.F. Warshel, A., Free energy perturbation calculations of DNA destabilization by base substitutions the effect of neutral guanine-thymine, adenine-cytosine and adenine-difluorotoluene mismatches, J. Phys. Chem. B 2000,104, 10092-10099. 

Table XIX contains stability constants for complexes of Ca2+ and of several other M2+ ions with a selection of phosphonate and nucleotide ligands (681,687-695). There is considerably more published information, especially on ATP (and, to a lesser extent, ADP and AMP) complexes at various pHs, ionic strengths, and temperatures (229,696,697), and on phosphonates (688) and bisphosphonates (688,698). The metal-ion binding properties of cytidine have been considered in detail in relation to stability constant determinations for its Ca2+ complex and complexes of seven other M2+ cations (232), and for ternary M21 -cytidine-amino acid and -oxalate complexes (699). Stability constant data for Ca2+ complexes of the nucleosides cytidine and uridine, the nucleoside bases adenine, cytosine, uracil, and thymine, and the 5 -monophosphates of adenosine, cytidine, thymidine, and uridine, have been listed along with values for analogous complexes of a wide range of other metal ions (700). Unfortunately comparisons are sometimes precluded by significant differences in experimental conditions.

Phenylglyoxal and alkoxyphenylglyoxals react selectively with the guanine moiety of nucleosides and nucleotides in phosphate buffer (pH 7.0) at 37°C for 5-7 min to give the corresponding fluorescent derivatives [12-15], as shown in Figure 6. Other nucleic acid bases and nucleotides (e.g., adenine, cytosine, uracil, thymine, AMP, CMP) do not produce derivatives under such mild reaction conditions. The fluorescent derivative emits chemiluminescence on oxidation with di-methylformamide (DMF) and H202 at pH 8.0-12 [14, 15],... 

In DNA the sugar molecule in the nucleotide is 2-deoxyribose, and in RNA it is ribose. The amine bases in DNA are adenine, thymine, cytosine, and guanine, symbolized by A, T, C, and G, respectively. RNA contains adenine, cytosine, and guanine, but thymine is replaced by the based uracil (Figure 16.16). The primary structure of nucleic acids is given by the sequence of the amine side chains starting from the phosphate end of the nucleotide. For example, a DNA sequence may be -T-A-A-G-C-T. 

The four bases whose sequence determines the hereditary information in ribonucleic acid (RNA), the naturally occurring polynucleotide, are adenine, cytosine, guanine, and uracil. These structures are as shown in Figure A. 

Length of the bridge containing adenine-cytosine base pairs only Lowest unoccupied molecular orbital Marcus reorganization energy Mass of the tunneling particle... 

The study of the nucleic acid bases is interesting because they possess many possible sites of protonation or electrophilic attack. Isopotential maps have been constructed for adenine, cytosine, and thymine.244 They may be used to study theoretically the proton affinities of the different atoms in these molecules. It is well known that protonation of cytosine, its nucleotide or nucleoside, occurs at N-394,245-247 (cf. Section II) alkylation also occurs at N-3.103-248-249 Nevertheless protonation of the oxygen of cytosine in DNA has been reported.250 The basic pA of cytosine is higher than that of adenine. The isopotential map in the molecular plane of cytosine (Tig. 8) shows that the potential well is deeper for N-3 than for 0 and the minimum for N-3 in cytosine is deeper than for any nitrogen in adenine. These maps, and their confrontation with the experimental facts have been discussed228-244... 

Sakurai K, Shinkai S (2000) Molecular recognition of adenine, cytosine, and uracil in a singlestrand RNA by a natural polysaccharide schizophyllan. J Am Chem Soc 122 4520-4521... 

Contrary to H-bonded nucleic acid base pairs discussed in the previous section, the nature of intermolecular interactions in complexes of stacked bases was analyzed more extensively. The values of minimal, maximal, and average total stabilization energies, corrected for BSSE, for a set comprising over 80 stacked bases, are plotted in Fig. 20.1. In the case of guanine-adenine and adenine-cytosine complexes, the results are presented for two sequence contexts, i.e., A/G-G/A and A/C-C/A. The symbol AA denotes the 2-oxo-adenine - complexes of oxidized bases, and this... 

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