Complementary sequence preferences of electron-capture dissociation and vibrational excitation in fragmentation of polypeptide polycations.

摘要: The combination of collision-activated dissociation, (CAD) and electron capture (ECD) yielded a 125% increase in protein identification. S-score was developed for measuring the information content MS/MS spectra. This measure made it possible to single out good quality spectra that were not identified by search engine. Poor data filtered out, streamlining identification process.A proteomics grade de novo sequencing approach enabling almost completely sequence 19% all with 95% reliability typical experiment.A new tool, Modificomb, identifying types modifications fast, reliable way developed. New have been discovered extent gel based turned be greater than expected.PhosTShunter sensitive phosphorylated peptides an dataset.Application these programs human milk samples led previously unreported potentially biologically important phosphorylation site.Peptide fragmentation has studied. It shown emphatically on dataset 15.000 CAD ECD different cleavage preferences respect amino acid context.Hydrogen rearrangement involving z• species investigated. Clear trends unveiled. elucidated mechanism hydrogen transfer.Partial side-chain losses potential ions reliably distinguishing Leu/Iso residues shown. Partial sidechain occurring far away from site detected.A strong correlation found between propensities acids towards peptide bond employing propensity accept solution backbone-backbone H-bonds form stable motifs. indicated same parameter governs formation secondary structures directs CAD.