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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A novel sea anemone peptide that inhibits acid-sensing ion channels

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Alexei Rodriguez, Armando [1] ; Salceda, Emilio [2] ; Georgina Garateix, Anoland [1] ; Zaharenko, Andre Junqueira [3] ; Peigneur, Steve [4] ; Lopez, Omar [2] ; Pons, Tirso [5] ; Richardson, Michael [6] ; Diaz, Maylin [1] ; Hernandez, Yasnay [1] ; Staendker, Ludger [7] ; Tytgat, Jan ; Soto, Enrique [2]
Total Authors: 13
[1] Ctr Bioprod Marinos CEBIMAR, Alturas Del Vedado 10400, Habana - Cuba
[2] Univ Autonoma Puebla, Inst Fisiol, Puebla 72750 - Mexico
[3] Butantan Inst, Genet Lab, BR-05503900 Sao Paulo - Brazil
[4] Univ Leuven KU Leuven, Toxicol Lab, B-3000 Louvain - Belgium
[5] Ctr Nacl Invest Oncol, Madrid 28029 - Spain
[6] Fundacao Ezequiel Dias FUNED, BR-30510010 Belo Horizonte, MG - Brazil
[7] Univ Ulm West, Kompetenzzentrum Ulm Peptide Pharmaceut U PEP, D-89081 Ulm - Germany
Total Affiliations: 7
Document type: Journal article
Source: Peptides; v. 53, p. 3-12, MAR 2014.
Web of Science Citations: 28

Sea anemones produce ion channels peptide toxins of pharmacological and biomedical interest. However, peptides acting on ligand-gated ion channels, including acid-sensing ion channel (ASIC) toxins, remain poorly explored. PhcrTx1 is the first compound characterized from the sea anemone Phymanthus crucifer, and it constitutes a novel ASIC inhibitor. This peptide was purified by gel filtration, ion-exchange and reversed-phase chromatography followed by biological evaluation on ion channels of isolated rat dorsal root ganglia (DRG) neurons using patch clamp techniques. PhcrTx1 partially inhibited ASIC currents (IC50 similar to 100 nM), and also voltage-gated K+ currents but the effects on the peak and on the steady state currents were lower than 20% in DRG neurons, at concentrations in the micromolar range. No significant effect was observed on Na voltage-gated currents in DRG neurons. The N-terminal sequencing yielded 32 amino acid residues, with a molecular mass of 3477 Da by mass spectrometry. No sequence identity to other sea anemone peptides was found. Interestingly, the bioinformatic analysis of Cys-pattern and secondary structure arrangement suggested that this peptide presents an Inhibitor Cystine Knot (ICK) scaffold, which has been found in other venomous organisms such as spider, scorpions and cone snails. Our results show that PhcrTx1 represents the first member of a new structural group of sea anemones toxins acting on ASIC and, with much lower potency, on K-v channels. Moreover, this is the first report of an ICK peptide in cnidarians, suggesting that the occurrence of this motif in venomous animals is more ancient than expected. (C) 2013 Elsevier Inc. All rights reserved. (AU)