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1 July 2003 Alteration of Protein Constituents Induced by Low-Energy (<35 eV) Electrons: II. Dissociative Electron Attachment to Amino Acids Containing Cyclic Groups
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Abstract

Abdoul-Carime, H. and Sanche, L. Alteration of Protein Constituents Induced by Low-Energy (<35 eV) Electrons: II. Dissociative Electron Attachment to Amino Acids Containing Cyclic Groups. Radiat. Res. 160, 86–94 (2003).

We report measurements of the desorption of anions from thin condensed films of tryptophan (Trp), histidine (His) and proline (Pro) stimulated by 5–35 eV electron impact. H, O, OH and CN desorb from Trp, His and Pro, whereas CH2 is observed only from Pro fragmentation. Below 12 eV, the anion yield functions exhibit resonant structures indicative of dissociative electron attachment. For all three amino acids, this process is likely to be initiated by the resonant capture of the incident electron at the NH3 –CH–…. .–COO and/or NH2–CH–…. .–COOH group of the molecule. Temporary electron attachment to the ring leads to anion desorption only for tryptophan and proline. The energy-averaged yields measured at the detector of the mass spectrometer are (4.9, 0.3 and 54.0) × 10−8 H/incident electron and (3.4, 2.9, 1.8) × 10−11 O/incident electron, respectively, from Trp, His and Pro dissociation. Fragmentation of amino acids is found to be as intense as that of the nucleic acid bases. These results are discussed within the context of radiobiological damage induced by secondary electrons.

H. Abdoul-Carime and L. Sanche "Alteration of Protein Constituents Induced by Low-Energy (<35 eV) Electrons: II. Dissociative Electron Attachment to Amino Acids Containing Cyclic Groups," Radiation Research 160(1), (1 July 2003). https://doi.org/10.1667/RR3025
Received: 9 December 2002; Accepted: 1 March 2003; Published: 1 July 2003
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