title: Two new scorpion toxins that target voltage-gated Ca2+ and Na+ channels.
abstract: This report describes the isolation, primary structure determination, and functional characterization of two similar toxins from the scorpion Parabuthus granulatus named kurtoxin-like I and II (KLI and KLII, respectively). KLII from P. granulatus is identical to kurtoxin from Parabuthus transvaalicus (a 63 amino-acid long toxin) whereas KLI is a new peptide containing 62 amino acid residues closely packed by four disulfide bridges with a molecular mass of 7244. Functional assays showed that both toxins, KLI and kurtoxin from P. granulatus, potently inhibit native voltage-gated T-type Ca(2+) channel activity in mouse male germ cells. In addition, KLI was shown to significantly affect the gating mechanisms of recombinant Na(+) channels and weakly block alpha(1)3.3Ca(V) channels expressed in Xenopus oocytes. KLI and kurtoxin from P. granulatus represent new probes to study the role of ion channels in germ cells, as well as in cardiac and neural tissue.
authors.affiliation: Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Apartado Postal 510-3 Cuernavaca 62210, Mexico.
authors.forename: Timoteo
authors.initials: T
authors.lastname: Olamendi-Portugal
authors.forename: Blanca Inés
authors.initials: BI
authors.lastname: García
authors.forename: Ignacio
authors.initials: I
authors.lastname: López-González
authors.forename: Jurg
authors.initials: J
authors.lastname: Van Der Walt
authors.forename: Karin
authors.initials: K
authors.lastname: Dyason
authors.forename: Chris
authors.initials: C
authors.lastname: Ulens
authors.forename: Jan
authors.initials: J
authors.lastname: Tytgat
authors.forename: Ricardo
authors.initials: R
authors.lastname: Felix
authors.forename: Alberto
authors.initials: A
authors.lastname: Darszon
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D015640:Ion Channel Gating / Q000502:physiology; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012605:Scorpions / Q000737:chemistry; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D013093:Spermatogonia / Q000166:cytology / Q000378:metabolism; D014118:Toxins, Biological / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D015220:Calcium Channels; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D015222:Sodium Channels; D014118:Toxins, Biological