UV Photo-dissociation of proline-containing peptide ions: Insights from molecular dynamics
Résumé
UV photodissociation of proline-containing peptide ions leads to unusual product ions. In this paper, we report laser-induced dissociation of a series of proline-containing peptides at 213 nm. We observe specific fragmentation pathways corresponding to the formation of (y-2), (a + 2) and (b + 2) fragment ions. This was not observed at 266 nm or for peptides which do not contain proline residues. In order to obtain insights into the fragmentation dynamics at 213 nm, a small peptide (RPK for arginine-proline-lysine) was studied both theoretically and experimentally. Calculations of absorption spectra and non-adiabatic molecular dynamics (MD) were made. Second and third excited singlet states, S2 and S3, lie close to 213 nm. Non-adiabatic MD simulation starting from S2 and S3 shows that these transitions are followed by C-C and C-N bond activation close to the proline residue. After this first relaxation step, consecutive rearrangements and proton transfers are required to produce unusual (y-2), (a + 2) and (b + 2) fragment ions. These fragmentation mechanisms were confirmed by H/D exchange experiments.
Mots clés
ELECTRON PHOTODETACHMENT DISSOCIATION
DISSOCIATION MASS-SPECTROMETRY
PROTONATED PEPTIDES
SURFACE-INDUCED DISSOCIATION
GAS-PHASE
DETACHMENT DISSOCIATION
SEQUENCE-ANALYSIS
TRYPTIC PEPTIDES
CAPTURE DISSOCIATION
:Photodissociation
Molecular dynamics
Proline-containing peptides
H/D exchange
Fragmentation
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peptPro.pdf (1.8 Mo)
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Supporting material peptPro.pdf (750.86 Ko)
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Origine | Fichiers produits par l'(les) auteur(s) |
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