Infrared spectroscopic studies of the main cellular components: The effect of hydration on proteins, nucleic acids and phospholipids spectra.

摘要

The research presented in the thesis was undertaken to examine effect of hydration of infrared spectra of the major cellular components: proteins, nucleic acids and phospholipids. A method was devised that utilizes KBr pellets to determine infrared bands of these biomolecules that are most sensitive to the variation in amount of bound water in the structure of these biomolecules. For proteins, an enormous increase in the absorption intensities of the amide I and amide II vibrations between dry and hydrated phases was observed. The intensity changes between dry and hydrated protein samples were interpreted in terms of variations in the dielectric constant of the immediate surroundings of a peptide linkage.;For nucleic acids, DNA and RNA, as well as phospholipids the symmetric and antisymmetric stretching vibrations of phosphate linkage, PO2 -, were found to be very sensitive to hydration, as both intensity changes as well as frequency shifts are observed. The frequency shifts were interpreted in terms of the conformational changes, whereas the increase in intensity may be due to an increase in a local dielectric in the vicinity of the polar and solvent exposed phosphate groups.