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Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas.
Biochemistry. 1998 Nov 03; 37(44):15353-62.B

Abstract

We describe the first potent and selective blocker of the class E Ca2+channel. SNX-482, a novel 41 amino acid peptide present in the venom of the African tarantula, Hysterocrates gigas, was identified through its ability to inhibit human class E Ca2+ channels stably expressed in a mammalian cell line. An IC50 of 15-30 nM was obtained for block of the class E Ca2+ channel, using either patch clamp electrophysiology or K+-evoked Ca2+ flux. At low nanomolar concentrations, SNX-482 also blocked a native resistant or R-type Ca2+ current in rat neurohypophyseal nerve terminals, but concentrations of 200-500 nM had no effect on R-type Ca2+ currents in several types of rat central neurons. The peptide has the sequence GVDKAGCRYMFGGCSVNDDCCPRLGCHSLFSYCAWDLTFSD-OH and is homologous to the spider peptides grammatoxin S1A and hanatoxin, both peptides with very different ion channel blocking selectivities. No effect of SNX-482 was observed on the following ion channel activities: Na+ or K+ currents in several cultured cell types (up to 500 nM); K+ current through cloned potassium channels Kv1.1 and Kv1. 4 expressed in Xenopus oocytes (up to 140 nM); Ca2+ flux through L- and T-type Ca2+ channels in an anterior pituitary cell line (GH3, up to 500 nM); and Ba2+ current through class A Ca2+ channels expressed in Xenopus oocytes (up to 280 nM). A weak effect was noted on Ca2+ current through cloned and stably expressed class B Ca2+ channels (IC50 > 500 nM). The unique selectivity of SNX-482 suggests its usefulness in studying the diversity, function, and pharmacology of class E and/or R-type Ca2+ channels.

Authors+Show Affiliations

Elan Pharmaceuticals Inc., Menlo Park, California 94025, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9799496

Citation

Newcomb, R, et al. "Selective Peptide Antagonist of the Class E Calcium Channel From the Venom of the Tarantula Hysterocrates Gigas." Biochemistry, vol. 37, no. 44, 1998, pp. 15353-62.
Newcomb R, Szoke B, Palma A, et al. Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas. Biochemistry. 1998;37(44):15353-62.
Newcomb, R., Szoke, B., Palma, A., Wang, G., Chen, X. h., Hopkins, W., Cong, R., Miller, J., Urge, L., Tarczy-Hornoch, K., Loo, J. A., Dooley, D. J., Nadasdi, L., Tsien, R. W., Lemos, J., & Miljanich, G. (1998). Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas. Biochemistry, 37(44), 15353-62.
Newcomb R, et al. Selective Peptide Antagonist of the Class E Calcium Channel From the Venom of the Tarantula Hysterocrates Gigas. Biochemistry. 1998 Nov 3;37(44):15353-62. PubMed PMID: 9799496.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas. AU - Newcomb,R, AU - Szoke,B, AU - Palma,A, AU - Wang,G, AU - Chen,X h, AU - Hopkins,W, AU - Cong,R, AU - Miller,J, AU - Urge,L, AU - Tarczy-Hornoch,K, AU - Loo,J A, AU - Dooley,D J, AU - Nadasdi,L, AU - Tsien,R W, AU - Lemos,J, AU - Miljanich,G, PY - 1998/11/4/pubmed PY - 1998/11/4/medline PY - 1998/11/4/entrez SP - 15353 EP - 62 JF - Biochemistry JO - Biochemistry VL - 37 IS - 44 N2 - We describe the first potent and selective blocker of the class E Ca2+channel. SNX-482, a novel 41 amino acid peptide present in the venom of the African tarantula, Hysterocrates gigas, was identified through its ability to inhibit human class E Ca2+ channels stably expressed in a mammalian cell line. An IC50 of 15-30 nM was obtained for block of the class E Ca2+ channel, using either patch clamp electrophysiology or K+-evoked Ca2+ flux. At low nanomolar concentrations, SNX-482 also blocked a native resistant or R-type Ca2+ current in rat neurohypophyseal nerve terminals, but concentrations of 200-500 nM had no effect on R-type Ca2+ currents in several types of rat central neurons. The peptide has the sequence GVDKAGCRYMFGGCSVNDDCCPRLGCHSLFSYCAWDLTFSD-OH and is homologous to the spider peptides grammatoxin S1A and hanatoxin, both peptides with very different ion channel blocking selectivities. No effect of SNX-482 was observed on the following ion channel activities: Na+ or K+ currents in several cultured cell types (up to 500 nM); K+ current through cloned potassium channels Kv1.1 and Kv1. 4 expressed in Xenopus oocytes (up to 140 nM); Ca2+ flux through L- and T-type Ca2+ channels in an anterior pituitary cell line (GH3, up to 500 nM); and Ba2+ current through class A Ca2+ channels expressed in Xenopus oocytes (up to 280 nM). A weak effect was noted on Ca2+ current through cloned and stably expressed class B Ca2+ channels (IC50 > 500 nM). The unique selectivity of SNX-482 suggests its usefulness in studying the diversity, function, and pharmacology of class E and/or R-type Ca2+ channels. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/9799496/Selective_peptide_antagonist_of_the_class_E_calcium_channel_from_the_venom_of_the_tarantula_Hysterocrates_gigas_ L2 - https://doi.org/10.1021/bi981255g DB - PRIME DP - Unbound Medicine ER -