P. Archirel, C. Houée-Levin, J. Marignier
Oct 2, 2019
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0
Influential Citations
3
Citations
Journal
The journal of physical chemistry. B
Abstract
The two inverse peptides methionine - valine (Met-Val) and valine - methionine (Val-Met) are investigated in an oxidative radiolysis process in water. The OH• species yields products with very different absorption spectra and concentration effects: Met- Val yields one main product with a band at about 400 nm and other products at higher energies, there is no concentration effect. Val-Met yields at least three products, with a striking concentration effect. Molecular simulations are performed, with a combination of the Monte-Carlo, DFT and Reaction Field methods. The simulation of the possible transients enables an interpretation of the radiolysis: (1) Met-Val undergoes an H atom uptake leaving mainly a neutral radical with a (2c-3e) SN bond, which cannot dimerize. Other radicals are present at higher energies. (2) Val-Met undergoes mainly an electron uptake leaving a cation monomer with a (2c-3e) SO bond and a cation dimer with a (2c-3e) SS bond. At higher energies neutral radicals are possible. This cation monomer can transfer a proton toward a neutral peptide, leaving a neutral radical.