Identification of structural elements of a scorpion α-neurotoxin important for receptor site recognition

Noam Zilberberg, Oren Froy, Erwann Loret, Sandrine Cestele, Dorit Arad, Dalia Gordon, Michael Gurevitz

Research output: Contribution to journalArticlepeer-review

109 Scopus citations

Abstract

α-Neurotoxins from scorpion venoms constitute the most studied group of modifiers of the voltage-sensitive sodium channels, and yet, their toxic site has not been characterized. We used an efficient bacterial expression system for modifying specific amino acid residues of the highly insecticidal α- neurotoxin LqhαIT from the scorpion Leiurus quinquestriatus hebraeus. Toxin variants modified at tight turns, the C-terminal region, and other structurally related regions were subjected to neuropharmacological and structural analyses. This approach highlighted both aromatic (Tyr10 and Phe17) and positively charged (Lys8, Arg18, Lys62, and Arg64) residues that (i) may interact directly with putative recognition points at the receptor site on the sodium channel; (ii) are important for the spatial arrangement of the toxin polypeptide; and (iii) contribute to the formation of an electrostatic potential that may be involved in biorecognition of the receptor site. The latter was supported by a suppressor mutation (E15A) that restored a detrimental effect caused by a K8D substitution. The feasibility of producing anti-insect scorpion neurotoxins with augmented toxicity was demonstrated by the substitution of the C-terminal arginine with histidine. Altogether, the present study provides for the first time an insight into the putative toxic surface of a scorpion neurotoxin affecting sodium channel gating.

Original languageEnglish
Pages (from-to)14810-14816
Number of pages7
JournalJournal of Biological Chemistry
Volume272
Issue number23
DOIs
StatePublished - 6 Jun 1997
Externally publishedYes

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