Biopolym. Cell. 2002; 18(4):351-355.
http://dx.doi.org/10.7124/bc.000618
Short Communications
Various point contacts between neutral and deprotonated carboxylic groups of amino acids and 2-aminopurine
1Potyahaylo A. L., 1Hovorun D. M.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680

Abstract

The complete family of point contacts between neutral or deprotonated acetic acid and 2-aminopurine has been first calculated in vacuum by semi-empirical quantum chemical method MNDO/H. Acetic acid simulated the side chains of glutamic and aspartic acids. It has been found that specific interaction of deprotonated acid with the base transfers the latter from the main N9H tautomeric form to the high energy N3H form with the 0.92 kcal/mol energy advantage and results in the formation of N3H...O , N2H...O point contact. However, the specific interaction of neutral ligand with 2-aminopurine does not cause any tautomeric transformations of the base; the most favourable point contact N9H...O, N3...HO with the 2.3 kcal/mol energy advantage is formed with its main N9H tautomeric form. In all cases carboxylate-ion provides about three times stronger interaction (its energy amounts to 5O kcal/mol and higher) than neutral carboxylic group.
Full text: (PDF, in Ukrainian)

References

[1] Koshland DE. [Molecular basis of enzyme catalysis and control]. Zh vsesoyuzhnogo khim obschestva im D I Mendeleeva. 1971; 16(2):158-64.
[2] Samijlenko SP, Bogdan TV, Trygubenko SA, Potyahaylo AL, Hovorun DM. Deprotonated carboxylic group of amino acids transforms adenine into its rare prototropic tautomers. Ukr Biokhim Zh. 2000;72(6):92-5.
[3] Samijlenko SP, Potyahaylo AL, Stepanyugin AV, Bogdan TV, Dzerzhyns'kyi ME, Hovorun DM. Specific interactions of izoguanine with neutral and deprotonated carboxylic group of amino acids: results af model quantum chemical calculations. Ukr Biokhim Zh. 2001;73(3):147—51.
[4] Samijlenko SP, Kondratyuk IV, Potyahaylo AL, Stepanyugin AV, Hovorun DM. Specific interactions of deprotonated carboxylic group with uracil and thymine provoke diketo - keto-enolic tautomeric transition in bases. Ukr Biokhim Zh. 2001; 73(4):128-31.
[5] Hovorun DM. A physico-chemical concept of biopolymers' functioning. Dopovidi Nats Akad Nauk Ukrainy. 2000; (2):171-5.
[6] Hovorun DM. A structural isomerism of nucleotide bases: AMI calculation. Biopolym Cell. 1997; 13(2):127-34.
[7] Poltev VI, Shuliupina NV, Bruskov VI. [Molecular mechanisms of the regularity of nucleic acid biosynthesis. Computer study of the role of polymerases in the formation of irregular pairs by modified bases]. Mol Biol (Mosk). 1996;30(6):1284-98.
[8] Broo A, Holm?n A. Ab initio MP2 and DFT calculations of geometry and solution tautomerism of purine and some purine derivatives. Chem Phys. 1996;211(1-3):147–61.
[9] Pullman B, Pullman A. Quantum biochemistry. Interscience Publishers. N. Y., 1963; 867 p.