Investigating substituent effects on the fragmentation spectra of protonated peptides modified to create N-terminal imines
Nelson, Robert; van Stipdonk, Michael; Patterson, Khiry.
Department of Chemistry and Biochemistry
Tandem mass spectrometry (MSn) and collision induced dissociation (CID) are among the most important tools used to identify peptides and proteins in proteomics. Fragmentation of gas-phase, protonated peptides creates product ions that reveal amino acid sequence. Recently we found that conversion of peptides to N-terminal imines (as Schiff bases) enhances the sequence information revealed by the MSn approach. Further investigation of substituent effects on the fragmentation spectra through the interchange of the aldehyde/ketone reactant in the modification step may reveal even more important sequence information. It is the goal of this research to prepare peptide-imines in the gas phase, investigate the influence of substituents on product ion distributions and assess improvements to MSn sequencing gained by the modification.