A DFT study of electron or hole localization in a peptide containing asparagin
Laboratoire de Chimie Physique (UMR 8000 du CNRS) , centre universitaire, 91405 Orsay Cedex, France
2 Laboratoire de Chimie Théorique (UMR 7616 du CNRS) , Université Paris VI, 4 place Jussieu, 75005 Paris, France
Corresponding author: a firstname.lastname@example.org
Published online: 13 September 2002
The mechanisms of protein degradation induced by ionisation are of great interest for radiobiology, improvement of mass spectroscopy and industrial processes such as radio sterilisation. Sequences containing asparagin are very sensitive especially if surrounded by glycine. Very few techniques allow a satisfying understanding of the processes induced by creation of an anionic or cationic site in a peptide. We used the methods of quantum chemistry (DFT/B3LYP with 6-31G* basis set) to characterise the geometry modifications induced in the cations or in the anions derived from peptide Gly Asn Gly. The cationic sites are localised mostly close to the first peptidic bond and induce a lengthening of the Ca–C(O) bond. Conversely the anionic sites are localised on a carbonyl function. Implications are discussed considering the radiolytic products and the proposed mechanisms.
PACS: 31.15.Ar – Ab initio calculations / 87.15.-v – Biomolecules: structure and physical properties
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002