title: Proteomics of the venom from the Amazonian scorpion Tityus cambridgei and the role of prolines on mass spectrometry analysis of toxins.
abstract: Scorpion venom are complex mixtures of peptides, known to cause impairment of ion-channel function in biological membranes. This report describes the separation of approximately 60 different components by high performance liquid chromatography and the characterization by Edman degradation and mass spectrometry of 26 peptides from the soluble venom of the Amazonian scorpion Tityus cambridgei. One of these peptides, named Tc48a, was fully characterized. It contains 65 amino acid residues, the C-terminal residue is amidated and it affects Na(+)-channels with a K(d) of about 82 nM. Furthermore, this report shows the thermo-instability of scorpion toxins subjected to electron spray ionization-mass spectrometry (ESI-MS). When a proline residue is located near the N-terminal region of the toxin, not stabilized by disulfide bridges, artificial components are generated by the mass spectrometer conditions, due to the cleavage of the peptide bond at the proline positions. This phenomenon was confirmed by using four model proteins (variable regions of immunoglobulins) studied by ESI-MS and matrix assisted laser desorption ionization-time of flight (MALDI-TOF)/MS.
authors.affiliation: Department of Molecular Medicine and Bioprocesses, National Autonomous University of Mexico, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico.
authors.forename: Cesar V F
authors.initials: CV
authors.lastname: Batista
authors.forename: Luis
authors.initials: L
authors.lastname: del Pozo
authors.forename: Fernando Z
authors.initials: FZ
authors.lastname: Zamudio
authors.forename: Sandra
authors.initials: S
authors.lastname: Contreras
authors.forename: Baltazar
authors.initials: B
authors.lastname: Becerril
authors.forename: Enzo
authors.initials: E
authors.lastname: Wanke
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D011392:Proline / Q000737:chemistry*; D040901:Proteomics; D012604:Scorpion Venoms / Q000737:chemistry*; D012605:Scorpions; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014118:Toxins, Biological / Q000032:analysis*
chemical_list: D012604:Scorpion Venoms; D014118:Toxins, Biological; D011392:Proline