Radiation Induced Molecular Damage Addressed by Terahertz Spectroscopy – A Theoretical Study

Nuclear radiation can seriously damage biological samples. Some radiation effects are the production of reactive radicals resulted from water radiolysis and random bond breakings, protein fragmentation, cross-linking or aggregation resulted from random ionizations in proteins. Similar effects were described in the case of X-rays irradiation. Therefore, we assumed that not only nuclear radiation, but also the lower energy X-rays produce flexibility changes in proteins that can be addressed by Terahertz (THz) spectroscopy. Here we simulated and compared the THz spectra of two Torpedo californica acetylcholinesterase structures that were exposed to synchrotron radiation (hard X-ray of ~13 keV) over different periods of time. Our results show a clear difference between simulated absorptions, which allows us to conclude that radiation induced changes in proteins structures and flexibility should be visible on THz spectra. By detecting even subtle effects produced by radiation softer than nuclear radiation, THz spectroscopy should be useful in detecting effects of higher energy radiation that is part of the chemical, biological, radiological and nuclear (CBRN) threat.