Ion irradiation induced direct damage to proteins and their components
  In our last paper, we have reported the direct interact between energetic ions and DNA, and its components, pointing out that damage to DNA is actually of highest biological consequence, as the integrity of DNA sequence is essential for biological function. Proteins are another kind of important biomolecules. Although much recent attention has been payed to ion irradiation initiated reaction cascades leading to DNA damage, the protein lesions induced by energetic ions remain virtually unexplored at the molecular scale (maybe because there are usually many copies of each protein, so a comparable level of damage is of much less biological impact). Except for DNA damage, an understanding of nascent events leading to radiolytic protein damage is also required in order to achieve a complete description of ionizing radiation effects on living cells. 
Wei Wang, Zengliang Yu, Wenhui Su