Electron attachment to the dipeptide alanyl-glycine

Dissociative electron attachment (DEA) to the simplest hetero dipeptide (alanyl-glycine) is studied by means of a beam experiment. The results are compared with those previously obtained from the single compounds alanine and glycine from which the dipeptide is formed. In addition to the resonances and DEA products formed from the single molecules, alanyl-glycine exhibits new resonant features right at threshold (≈0 eV energy) and additional fragments which arise from the cleavage of the peptide and N–Cα bond. A further strong reaction leads to the loss of a neutral water molecule. These results clearly demonstrate that the dipeptide is considerably more sensitive towards low energy electrons than its components, which is of particular relevance with respect of radiation damage of biomolecular systems.