Identification of tyrosine sulfation in Conus pennaceus conotoxins alpha-PnIA and alpha-PnIB: further investigation of labile s.
Journal of Mass Spectrometry
447 - 454.
Liquid chromatography/electrospray ionization mass spectrometry was used to investigate the peptide composition of the venom of Conus pennaceus, a molluscivorous cone shell from the Red Sea. Based on observed M(r)s, this venom contained all known conotoxins previously isolated and identified from this species. Interestingly, the doubly protonated species of only two of these conotoxins, alpha-PnIA and alpha-PnIB, showed additional related ions at +40 m/z (+80 Da), indicating the presence of either sulfation or phosphorylation in both components. High-performance liquid chromatographic (HPLC) fractions containing these two conotoxins were examined by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry in both positive and negative ion modes, as well as by MALDI high-energy collision-induced dissociation. These experiments established the presence of a single sulfated tyrosine residue within both alpha-PnIA and alpha-PnIB. Hence their post-translationally modified sequences are GCCSLPPCAANNPDY(S)C- NH2 (alpha-PnIA) and GCCSLPPCALSNPDY(S)C-NH2 (alpha-PnIB). This assignment was supported by comparison of their mass spectral behavior with that of known sulfated and phosphorylated peptides. This data clarified further the distinguishing features of the ionization and fragmentation of such modified peptides. Selective disulfide folding of synthetic alpha-PnIB demonstrated that both sulfated and non-sulfated toxins co-elute on reversed-phase HPLC and that alpha-PnIB possesses the same disulfide connectivity as other 'classical' alpha-conotoxins reported previously
|Title:||Identification of tyrosine sulfation in Conus pennaceus conotoxins alpha-PnIA and alpha-PnIB: further investigation of labile s|
|Additional information:||UI - 99242956 LA - Eng RN - 0 (alpha-conotoxin PnIA) RN - 0 (alpha-conotoxin PnIB) RN - 0 (Mollusk Venoms) RN - 0 (Oligopeptides) RN - 55520-40-6 (Tyrosine) PT - JOURNAL ARTICLE ID - RR01614/RR/NCRR DA - 19990623 IS - 1076-5174 SB - M CY -ENGLAND JC - CMB AA - Author EM - 199908|
|Keywords:||Tyrosine, S, Oligopeptides, Id, alpha conotoxin PnIA, alpha conotoxin PnIB, Amino Acid Sequence, Animal, California, chemistry, Methods, Molecular Sequence Data, Mollusk Venoms, peptides, Phosphorylation, Spectrum Analysis, Mass, Support, Non-U.S.Gov't, Support, U.S.Gov't, P.H.S., Disulfides|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > Biosciences (Division of)|
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