Structure determination of two conotoxins from Conus textile by a combination of matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry and biochemical methods.
Two highly modified conotoxins from the mollusc Conus textile, epsilon-TxIX and Gla(1)-TxVI, were characterized by matrix-assisted laser desorption/ionization and electrospray mass spectrometry and also by electrospray ionization tandem and triple mass spectrometry in combination with enzymatic cleavage and chemical modification reactions. The mass spectrometric studies allowed the confirmation of the sequence determined by Edman degradation and assignment of unidentified amino acid residues, among which bromotryptophan residues and an O-glycosylated threonine residue were observed. Methyl esterification was found necessary for the site-specific assignment of the Gla residues in the peptides.
Kalume
D E
DE
Department of Molecular Biology, University of Southern Denmark, Odense University, Campusvej 55, DK-5230 Odense M, Denmark.
Stenflo
J
J
Czerwiec
E
E
Hambe
B
B
Furie
B C
BC
Furie
B
B
Roepstorff
P
P
D000478:Alkylation; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D020916:Conotoxins / Q000737:chemistry* / Q000302:isolation & purification; D004220:Disulfides / Q000737:chemistry; D006868:Hydrolysis; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008978:Mollusk Venoms / Q000737:chemistry*; D010084:Oxidation-Reduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000596:Amino Acids; D020916:Conotoxins; D004220:Disulfides; D008978:Mollusk Venoms; C405608:conotoxin TxVI, Gla(1)-; C400785:epsilon conotoxin TxIX