NATURAL SCIENCES

Journal of fundamental
and
applied researches

MODELING OF THE STRUCTURE AND VIBRATIONAL SPECTRA OF THE MAJOR AMINO ACIDS OF LYSINE AND ARGININE IN AQUEOUS SOLUTION

2017. 3, pp. 85-94

Ten Galina N. - D.Sc. (Physics and Mathematics), Professor, N.G. Chernyshevsky Saratov State University, 83 Astrakhanskaya Str., Saratov, 410012, Russian Federation, TenGN@yandex.ru

Scherbakova Natalya E. - Junior Researcher, Russian Research Anti-Plague Institute "Microbe", 46 Universitetskaya Str., Saratov, 410005, Russian Federation, hainl@yandex.ru

Baranov Viktor I. - V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry of the RAS, 19 Kosygina Str., Moscow, 119991, Russian Federation, baranov_50@mail.ru

Performed has been the calculation of IR spectra of zwitterionic-ionic forms of the basic lysine and arginine amino acids for the aqueous solution using two methods that take into account the influence of van der Waals forces (model of the self-consistent reaction field SCRF) and the hydrogen bonds, formed by water molecules with molecules of arginine and lysine, on the vibrational spectra of amino acids. Discussed have are various molecular models - zwitterionic-ionic forms with positively charged single and zero charge amino acid residues and complexes with water molecules, forming hydrogen bonds either with bipolar group or with an amino acid residue. Comparison of the calculated spectra with the experimental IR spectra of absorption has showed that the best agreement for Lys is achieved in case of molecular structure, on the vibrational spectrum of which intermolecular influence of both van der Waals forces and hydrogen bonds between the bipolar group and the water molecules was exerted simultaneously. Positively charged amino acid residue and water molecules interact via van der Waals forces (dipole-dipole interaction). For Arg, experimental spectrum of water solution can be represented as a superposition of the spectra of two molecular structures - structure that takes into account the formation of hydrogen bonds between water molecules and atoms N and O atoms of the bipolar group of positively charged Arg form, and molecular structure corresponding to neutral form of the amino acid Arg residue, being also under the influence of van der Waals forces.

Key words: , , - , , , , , , , , lysine, arginine, zwitterionic-ionic form, aqueous solution, IR spectrum, calculation, interpretation, complexe

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