Title: Signature Ions in MS/MS Spectra for Dansyl-Aminohexyl-QQIV Adducts on Lysine.
Authors: Schopfer, Lawrence M; Lockridge, Oksana
Published In Molecules, (2020 Jun 08)
Abstract: Bacterial transglutaminase was used to label human plasma proteins with fluorescent tags. Protein lysines were modified with dansyl-epsilon-aminohexyl-Gln-Gln-Ile-Val-OH (dansylQQIV), while protein glutamines were modified with dansyl cadaverine. Labeled proteins included human butyrylcholinesterase, apolipoprotein A-1, haptoglobin, haptoglobin-related protein, immunoglobulin heavy chain, and hemopexin. Tryptic peptides were analyzed by LC-MS/MS on an Orbitrap Fusion Lumos mass spectrometer. Modified residues were identified in Protein Prospector and Proteome Discoverer searches of mass spectrometry data. The MS/MS fragmentation spectra from dansylQQIV-modified peptides gave intense peaks at 475.2015, 364.1691, 347.1426, 234.0585, and 170.0965 m/z. These signature ions are useful markers for identifying modified peptides. Human butyrylcholinesterase retained full activity following modification by dansylQQIV or dansyl cadaverine.
PubMed ID: 32521655
MeSH Terms: Butyrylcholinesterase/chemistry*; Cadaverine/chemistry*; Dansyl Compounds/chemistry*; Glutamine/chemistry*; Humans; Lysine/chemistry*; Tandem Mass Spectrometry/methods*