Mass spectrometric sequencing of synthetic peptides containing alpha, alpha-dialkylated amino acid residues by MALDI post-source decay analysis.
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), a method well-suited for mass determination of biomolecules, has been used to analyze fragment ions generated by post-source decay (PSD) of synthetic peptaibols containing high proportions of the sterically hindered amino acids alpha-amino isobutyric acid (Aib) and isovaline (Iva). Since peptaibols do not have a free N-terminal amino group or side chains subject to protonation, the analyzed peptides saturnisporin SA III, trichotoxin A-50 and chrysospermin B were shown to provide preferred N-terminal and C-terminal a, b, and y fragments as sodium adduct. Additionally, a cleavage of the labile Aib-Probond was observed for all peptides investigated. The fragmentation pattern allowed confirmation of the primary structure and, therefore, demonstrated the usefulness of MALDI-PSD mass spectrometry for sequence analysis of the peptaibols.
Wenschuh
H
H
Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.
Suckau
D
D
Rapp
U
U
Bienert
M
M
Krause
F
F
D000478:Alkylation; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D000621:Aminoisobutyric Acids / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D017421:Sequence Analysis / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014633:Valine / Q000737:chemistry
D000596:Amino Acids; D000621:Aminoisobutyric Acids; D010455:Peptides; C100049:2-aminoisobutyric acid; C032737:isovaline; D014633:Valine