By theoretical conformational analysis method have been investigated the сonformational properties of immunostimulating hexapeptide, obtained from human casein by enzymatic digestion. Conformational analysis indicate that the spatial structure of hexapeptide can be described by set of low-energy conformations. It is shown that immunostimulating hexapeptide forms energetically favoured conformations with compact folded shapes of backbone. Calculations produced the values of all dihedral angles of the backbones and side chains and also intra- and inter-residue interactions energy contributions at the preferred conformations of hexapeptide. The comparison of the geometric and energetic parameters of stable conformations of hexapeptide permit to determine the conformational flexible and conservative segments of molecule.
immunostimulating hexapeptide, phagocytosis conformation, theoretical conformational analysis, flexibility
1. Parker F., Migliore-samour D., Floc'h F.,Zerial A., Werner G.H., Jollles J., Casaretto M., Zahn H., Jolles P., Immunostimulating hexapeptide from human casein :amino acid sequence, synthesis and biological properties. Eur. J. Biochem., 1984, vol. 45, pp. 677-682.
2. Jaziri M., Migliore-Samour D., Casabianca-Pignède M.-R. ,Keddad K., Morgat J.K. , Jollès P. Specific binding sites on human phagocytic blood cells for Gly-Leu-Phe and Val-Glu-Pro-Ile-Pro-Tyr, immunostimulating peptides from human milk proteins. Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1992, vol. 1160, iss. 3, pp. 251-261
3. Rysz J., Redliński A., Mudyna J., Lucia M. Synthesis and immunomodulatory activity of novel analogues of human beta-casein fragment [54-59]. Acta pol pharm., 2000, vol. 57, pp. 11-14.
4. Momany F., McGuire R., Burgess A., Scheraga H. Energy parameters in polypeptides. Geometric parameters, partial atomic charges, non bonded interaction for naturally occurring amino acid. J. Phys. Chem., 1975, vol. 79, pp. 2361-2381.
5. Popov E.M. Quantative approach to conformations. Int. J. Quantum Chem., 1979, vol. 16, pp. 707-737.
6. IUPAC-IUB Quantity. Units and Symbols in Physical Chemistry. Blackwell Scientific Publications, Oxford. 1988, vol. 39, 233 p.
7. Maksumov I.S., Ismailova L.I., Godjaev N.M The program for semiempirical calculation of conformations of the molecular complexes. Russ. J. Struct. Khim., 1983, vol. 24, pp. 147-148.
8. Agaeva G.A., Agaeva U.T., Godjaev N.M The spatial organization of human hemokinin-1 and mouse/rat hemokinin-1 molecules. Russ. Biophysics, 2015, vol. 60, pp. 365-377.
