title: Five-membered ring formation in unimolecular reactions of peptides: a key structural element controlling low-energy collision-induced dissociation of peptides.
abstract: Unimolecular fragmentation reactions of peptides in low-energy collision-induced dissociation are reviewed in the mechanistic context of five-membered ring formation. This structure of intermediates or of fragment ions is recognized as a key element that governs unimolecular peptide fragmentation within the structural framework determined by the peptide backbone and its side-chains. A collection of collision-induced dissociation reactions is presented covering (i) b-ion formation, (ii) the fragmentation of N-terminally acylated peptides, (iii) neutral loss of the C-terminal amino acid in alkali or silver cationized peptides, (iv) the fragmentation of isoAsp-containing peptides and (v) the fragmentation of negatively charged Asp- or Glu-containing peptides. It appears that for all possible nucleophile-electrophile interactions leading to a five-membered ring structure an associated unimolecular peptide fragmentation reaction can be observed.
authors.affiliation: Central Spectroscopy, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schlosser
authors.forename: W D
authors.initials: WD
authors.lastname: Lehmann
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003500:Cyclization; D018698:Glutamic Acid / Q000737:chemistry; D013058:Mass Spectrometry; D015394:Molecular Structure; D010446:Peptide Fragments / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*
chemical_list: D010446:Peptide Fragments; D010455:Peptides; D001224:Aspartic Acid; D018698:Glutamic Acid