ECAMP 15

In this communication we present how ionizing radiation influences the formation of peptide bonds in clusters of amino acids in the gas phase. In the past, simulations and experiments were carried out in parallel to understand the possible mechanisms involved[1,2]. Due to these promising previous results, we have expanded the study, including clusters of other amino acids. The main objective of this study is to evaluate the conditions of peptide bond formation in pure clusters of glycine, threonine, valine, serine and cysteine in the gas phase induced by collisions with alpha particles.

Experimentally, mass spectrometry is used to analyze the charged species formed after the collision with the highly charged ions. From the theoretical point of view, first the search for conformers is carried out using the CREST program[3], and then the structures obtained are further reoptimized with the Gaussian16 software[4] using the density functional theory DFT. The second stage of the work has been to make an analogous study, but on protonated clusters, since in these species believed to play the key role in the experiments. Finally, we have explored the potential energy surfaces to locate the transition states that explains the mechanism for peptide bond formation from the protonated clusters, also using DFT.