The dehydroalanine effect in the fragmentation of ions derived from polypeptides

Tandem mass spectrometry is a powerful approach for the analysis of peptides and proteins due to the primary structural information inherent in the observed products. The fragmentation of peptides and proteins depends heavily on the sequence and ion type of the species of interest. In this perspective special feature article, Scott McLuckey and co-authors show that peptides and proteins containing dehydroalanine, a nonproteinogenic amino acid with an unsaturated side-chain, undergo enhanced cleavage of the N-Cα bond of the dehydroalanine residue to generate c- and z-ions. Since these fragment ion types are not commonly observed upon activation of positively charged even-electron species, they can be used to identify dehydroalanine residues and localize them within the peptide or protein chain. Scott McLuckey is Professor of Chemistry at Purdue University (West Lafayette, IN). His research interests are centered on gas-phase ion chemistry and instrumentation for organic and biological mass spectrometry.