Effects of recombinant neurotoxins on single Na+ channels in isolated rat hippocampal neurons

Hui Xiang, Lei Wang, Jihong Cui, Jianyang Du, Ke Wang, Anlong Xu

Research output: Contribution to journalArticlepeer-review

Abstract

Four recombinant neurotoxins Hk2a, Hk7a, Hk8a, Hk16a, originally from a sea anemone species Anthopleura sp., were obtained by fusion expression of their genes in Escherichia coli. These neurotoxins were composed of 47 amino acid residues, among which the differences were found at positions 14, 22, 25, and 37, respectively. The effects of the four neurotoxins on single-channel current of sodium in rat hippocampal neurons were studied by cell-attached patch clamp. Each neurotoxin 2 μM could modulate the sodium channel by prolonging the opening dwell time and increasing the open probability, but did not change the amplitude of sodium channel currents. Based on the studies of the structure-function relationship, we found that Hk7a displayed the biggest increase of the open probability because His14 (from Arg14) makes its structure seem more compact in comparison with the other three toxins and Ap-A. Phe25 (Hk8a, Hk16a), which varied from Ala25 (Hk2a, Hk7a), showed that phenyl group might interfere with other key amino acid residue to decrease the activity of toxins. Arg37 (from His37) in Hk8a contributed to decrease of open probability. In our work, it was shown that these important amino acid sites might provide a reliable proof for the future pharmaceutical design.

Original languageEnglish (US)
Pages (from-to)244-255
Number of pages12
JournalJournal of Biochemical and Molecular Toxicology
Volume23
Issue number4
DOIs
StatePublished - Jul 2009
Externally publishedYes

Keywords

  • Cell-attached patch clamp
  • Hippocampal neurons
  • Sea anemone neurotoxin
  • Single-channel current
  • Sodium channel

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Toxicology
  • Health, Toxicology and Mutagenesis

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