Pi5 and Pi6, two undescribed peptides from the venom of the scorpion Pandinus imperator and their effects on K+-channels
Por:
Olamendi-Portugal, T., Csoti, A., Jimenez-Vargas, J. M., Gomez-Lagunas, F., Panyi, G., Possani, L. D.
Publicada:
1 jul 2017
Categoría:
Toxicology
Resumen:
This work reports the isolation, chemical and functional
characterization of two previously unknown peptides purified from the
venom of the scorpion Pandinus imperator, denominated Pi5 and Pi6. Pi5
is a classical K+-channel blocking peptide containing 33 amino acid
residues with 4 disulfide bonds. It is the first member of a new
subfamily, here defined by the systematic number alpha-KTx 24.1. Pi6 is
a peptide of unknown real function, containing only two disulfide bonds
and 28 amino acid residues, but showing sequence similarities to the
kappa-family of K-channel toxins. The systematic number assigned is
kappa-KTx2.9. The function of both peptides was assayed on Drosophila
Shab and Shaker K+-channels, as well as four different subtypes of
voltage-dependent K+-channels: hKv1.1, hKv1.2, hKv1.3 and hKv1.4. The
electro-physiological assays showed that Pi5 inhibited Shaker B, hKv1.1,
hKv1.2 and hKv1.3 channels with Kd = 540 nM, KD = 92 nM and Kd = 77 nM,
respectively, other studied channels were not affected. Of the channels
tested only hKv1.2 and hKv1.3 were inhibited at 100 nM concentration of
Pi6, the remaining current fractions were 68% and 77%, respectively.
Thus, Pi5 and Pi6 are high nanomolar affinity nonselective blockers of
hKv1.2 and hKv1.3 channels. (C) 2017 Elsevier Ltd. All rights reserved.
Filiaciones:
Olamendi-Portugal, T.:
Univ Nacl Autonoma Mexico, Dept Med Mol & Bioproc, Inst Biotecnol, Ave Univ 2001, Cuernavaca 62210, Morelos, Mexico
Csoti, A.:
Univ Nacl Autonoma Mexico, Dept Fisiol, Fac Med, Mexico City 04510, DF, Mexico
Jimenez-Vargas, J. M.:
Univ Nacl Autonoma Mexico, Dept Med Mol & Bioproc, Inst Biotecnol, Ave Univ 2001, Cuernavaca 62210, Morelos, Mexico
Gomez-Lagunas, F.:
Univ Debrecen, Res Ctr Mol Med, Fac Med, Dept Biophys & Cell Biol, 1 Egyet Ter, H-4032 Debrecen, Hungary
Panyi, G.:
Univ Nacl Autonoma Mexico, Dept Fisiol, Fac Med, Mexico City 04510, DF, Mexico
Possani, L. D.:
Univ Nacl Autonoma Mexico, Dept Med Mol & Bioproc, Inst Biotecnol, Ave Univ 2001, Cuernavaca 62210, Morelos, Mexico
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