Boryskina O. Energies of hydrogen bond that contribute to stabilization of conformation of collagen structures

The subject of the study is the conformation and stability of hydrated collagen structures, namely polypeptide poly(Gly-Pro-Pro), collagen type I and mineralized collagen type I. The methods of Infrared and Raman spectroscopy, quartz piezogravimetry and differential microwave dielectrometry and a numerical analysis of frequencies of stretching carbonyl vibrations are used. The aim of the work is to perform a quantitative estimation of enthalpies of peptide-peptide and peptide-water hydrogen bonds in different collagen structures. Application of the developed numerical algorithm has enabled us to compute the frequencies of the components of fine structure of the Amide I band in Infrared and Raman spectra of model collagen polypeptide with various primary structures. On the basis of the results obtained, the assignments of the components of the experimental Infrared and Raman spectra of poly(Gly-Pro-Pro) and collagen have been made. We have estimated the quantities of water molecules in different layersof the hydration shell of the studied collagen structures. It has been shown that the native conformation of collagen triple helix forms after completion of its internal hydration shell and partial filling of the external hydration shell. It has been shown that mineralization leads to partial screening of hydration centers of collagen from water molecules and alteration of its conformation. Enthalpies of peptide-peptide hydrogen bonds and enthalpies of hydration have been found. The results obtained give new information about the mechanisms of interaction within the collagen-water and collagen-water-hydroxyapatite systems and open new possibilities for use of collagen in medicine. The areas of implication are molecular biophysics and medicine.