Study on the variations of molecular structures of some biomolecules induced by free electron laser using FTIR spectroscopy

In this study, free electron laser (FEL) with selective wavelength was used to induce structure changes of biomolecules, which were characterized by FTIR spectroscopy. For understanding of the interactions between FEL and biomolecules as well as biological tissues, the biomolecules investigated are ATP, ADP, AMP, t-RNA, D-ribose and the complex of SmCl3-D-ribose. Their FTIR spectra before and after irradiation of FEL show molecular structure variations of the samples after irradiation of FEL, especially the rearrangement of their hydrogen bond networks. Along with the various irradiation wavelengths, irradiation time and molecular structures, the changes after irradiation are different for these molecules. In the FTIR spectra after irradiation, the phenomenon that the bands split into several peaks indicates the existence of several structures, conformations and configurations, which may be prompted by multiple photons process induced by FEL. After irradiation, the changes in their IR spectra indicate the occurrence of stable or metastable states of the molecules after irradiation, which illustrated that IR spectroscopy is a sensitive probe of molecular structure and provides us a method to detect the information related to the mechanism of the irradiation process. (c) 2007 Elsevier B.V. All rights reserved.