Referenced in: none

Automatically associated channels: Kv2.1 , Slo1

Title: Solution structure and functional characterization of jingzhaotoxin-XI: a novel gating modifier of both potassium and sodium channels.

Authors: Zhi Liao, Chunhua Yuan, Meichun Deng, Jiang Li, Jinjun Chen, Yuejun Yang, Weijun Hu, Songping Liang

Journal, date & volume: Biochemistry, 2006 Dec 26 , 45, 15591-600

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17176080

Abstract
JZTX-XI is a peptide toxin isolated from the venom of the Chinese spider Chilobrachys jingzhao. It contains 34 residues including six cysteine residues with disulfide bridges linked in the pattern of I-IV, II-V, and III-VI. Using 3'- and 5'-RACE methods, the full-length cDNA was identified as encoding an 86-residue precursor of JZTX-XI. In the electrophysiological assay, JZTX-XI shows activity toward the Kv2.1 channel in a way similar to hanatoxin1 and SGTx1 that both the activation and the deactivation processes are affected, which is in accordance with the high sequence homology among them (over 60% identity). On the other hand, JZTX-XI also exhibits specific interaction against the Nav channels of rat cardiac myocytes with a significant reduction in the peak current and slowing of channel inactivation. The solution structure of native JZTX-XI was determined by 1H NMR methods to identify the structural basis of these specific activities. Structural comparison of JZTX-XI with other gating modifier toxins shows that they all adopt a similar surface profile, a hydrophobic patch surrounded by charged residues such as Arg or Lys, which might be a common structural factor responsible for toxin-channel interaction. JZTX-XI might be an ideal tool to further investigate how spider toxins recognize various ion channels as their targets.