Influence of Size on Apparent Scrambling of Sequence During CID of b-Type Ions

We investigated the influence of peptide size on the apparent loss of sequence during collision-induced dissociation (CID) of b ions using a group of peptides containing from between 4 and 10 residues. Although scrambling of sequence for b3+ generated from tetrapeptides is minimal, significant formation of nondirect sequence ions (i.e., ions for which scrambling has apparently occurred) was observed for all larger b ions included in the study.

Graphical AbstractMultiple-stage CID experiments demonstrate loss of internal residues and remarkable similarity of product ion spectra among bn ions from permuted sequence isomers. The results support the hypothesis that significant sequence scrambling can occur following fragmentation of b-type ions.Figure optionsDownload high-quality image (179 K)Download as PowerPoint slide