Adenine-uracil interactions

The adenine-uracil interaction that involves two hydrogen bonds (Ka = lO M VCDCls) is weak and nonspecific compared with the guanine-cytosine interaction, which involves three hydrogen bonds (Ka = 10 -10 M VCDCls) that are... 

Sarai, A., and M. Saito. 1984. Theoretical Studies on the Interaction of Proteins with Base Paris. I. Ab Initio Calculation for the Effect of H-Bonding Interaction of Proteins on the Stability of Adenine-Uracil Pair. Int. J. Quantum Chem. 25, 527-533. 

Another pyrimidine base, uracil, is found in RNA instead of thymine. Base pairing between adenine and uracil involves two hydrogen bonds and resembles the adenine-thymine interaction. This type of base pairing is of importance in transcription, the synthesis of messenger RNA (see Section 14.2.5). 

One of the most prominent hydrogen-bonded systems is DNA. Despite numerous experimental and theoretical investigations on vibrational spectra of nucleic acid bases [7-13], information on inter- and intramolecular interactions in base pairs and DNA oligomers is still limited [14-25]. A recent example is the work on single adenine-uracil (AU) base pairs in the Watson-Crick geometry in solution, which showed an enhancement of vibrational energy... 

The stabilizing role of C-H- O = C contacts in base pairs was evaluated for the Watson Crick adenine-uracil (AU) pair by Starikov and Steiner [125]. Their ab initio calculations indicated these bonds contributed only about 6% to the total interaction energy. A better estimate might be achieved via the correlated calculations of the dimer of pyrimidine [126] (related to DNA base pairs) like that shown in Fig. 3. This dimer does not contain any conventional H-bonds,... 

The interaction between adenine and uracil occurs via two hydrogen bonds, while in the case of cytosine and guanine, there are three. 

The contents of the nucleic acid bases in the poly-L-lysine derivatives were determined by UV spectra of the polymers after hydrolysis The polymers were hydrolyzed in 6 N-hydrochloric acid at 105°C for 24 hr, into lysine dihydrochloride and the carboxyethyl derivatives of the nucleic acid bases. The quantitative calculation was made relative to the standard sample of the carboxyethyl derivative of the nucleic acid bases. The analytical data are listed in Table 1. It was found that the thymine and uracil derivatives was completely substituted to polylysine. Low value in case of adenine base in the polymer may be attributed to the unstability of the activated ester, Ade-PNP (2), and may also be explained in terms of the steric interaction among bulky pendant groups of the polymer. When the poly-L-lysine containing about 50 mol % adenine units was again treated with Ade-PNP, the adenine unit content in the polymer increased up to 74 mol %(,] ). 

Adsorption of adenine and coadsorption of adenine-thymine and uracil-thymine on Au(lll) has been reported [300]. Adenine was chemisorbed in two different states. Mutual interaction between adenine and thymine was detectable only at... 

The template polymerization was carried out at GO C in dimethyl sulfoxide/ethylene glycol mixture using AIBN as radical initiator. It was found that under these conditions interaction between adenine and uracil groups is remarkable. 

Spectral data (Amax and AE, and e x 10 3) for the pyrimidine bases investigated in a few representative papers are collected in Table XXVIII. The absorption bands are denoted by the capital letters A, B, C, etc. In Table XXVIII we have listed the results of the vacuum ultraviolet measurements by Yamada and Fukutome428 (cf. also ref. 429), who measured the spectra of sublimed films of cytosine, thymine, uracil (and also of guanine and adenine) down to 120 nm at room temperature. Several remarkable absorption peaks were found below 190 nm in addition to the already known ones near 260 and 200 nm. A weak absorption at 230-240 nm in cytosine was not indicated in the sublimed films of the molecule,428 but was visible in the stretched polyvinyl alcohol film spectrum.432 Crewe et al.i3° studied the interactions of fast electrons with the five nucleic acid bases and measured the energy-loss spectra of 20 keV electrons transmitted through thin films of these bases. These last data are also listed in Table XXVIII for comparison with the other spectral findings. 

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