title: Mass spectrometric characterization of lipid-modified peptides for the analysis of acylated proteins.
abstract: The analysis of acylated proteins by mass spectrometry (MS) has largely been overshadowed in proteomics by the analysis of glycosylated and phosphorylated proteins; however, lipid modifications on proteins are proving to be of increasing importance in biomedical research. In order to identify the marker ions and/or neutral loss fragments that are produced upon collision-induced dissociation, providing a means to identify the common lipid modifications on proteins, peptides containing an N-terminally myristoylated glycine, a palmitoylated cysteine and a farnesylated cysteine were chemically synthesized. Matrix-assisted laser desorption/ionization time-of-flight time-of-flight (MALDI-TOF-TOF), electrospray ionization quadrupole time-of-flight (ESI Q-TOF), and electrospray ionization hybrid triple-quadrupole/linear ion trap (ESI QqQ(LIT)) mass spectrometers were used for the analysis. The peptide containing the N-terminally myristoylated glycine, upon CID, produced the characteristic fragments a1 (240.4 Th) and b1 (268.4 Th) ions as well as a low-intensity neutral loss of 210 Da (C14H26O). The peptides containing a farnesylated cysteine residue fragmented to produce a marker ion at a m/z of 205 Th (C15H25) as well as other intense farnesyl fragment ions, and a neutral loss of 204 Da (C15H24). The peptides containing a palmitoylated cysteine moiety generated neutral losses of 238 Da (C16H30O) and 272 Da (C16H32OS); however, no marker ions were produced. The neutral losses were more prominent in the MALDI-TOF-TOF spectra, whereas the marker ions were more abundant in the ESI QqQ(LIT) and Q-TOF mass spectra.
authors.affiliation: The Biomedical Research Centre, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hoffman
authors.forename: Juergen
authors.initials: J
authors.lastname: Kast
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D008055:Lipids / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010446:Peptide Fragments / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000737:chemistry*
chemical_list: D008055:Lipids; D010446:Peptide Fragments; D010455:Peptides; D011506:Proteins