Two new scorpion toxins that target voltage-gated Ca2+ and Na+ channels.
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.
Olamendi-Portugal
Timoteo
T
Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Apartado Postal 510-3 Cuernavaca 62210, Mexico.
García
Blanca Inés
BI
López-González
Ignacio
I
Van Der Walt
Jurg
J
Dyason
Karin
K
Ulens
Chris
C
Tytgat
Jan
J
Felix
Ricardo
R
Darszon
Alberto
A
Possani
Lourival D
LD
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
D015220:Calcium Channels; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D015222:Sodium Channels; D014118:Toxins, Biological