Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning

Steve Peigneur, Yoko Yamaguchi, Chihiro Kawano, Takeru Nose, Selvanayagam Nirthanan, Ponnampalam Gopalakrishnakone, Jan Tytgat, Kazuki Sato

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Peptide toxins from scorpion venoms constitute the largest group of toxins that target the voltage-gated potassium channel (Kv). Spinoxin (SPX) isolated from the venom of scorpion Heterometrus spinifer is a 34-residue peptide neurotoxin cross-linked by four disulfide bridges. SPX is a potent inhibitor of Kv1.3 potassium channels (IC 50 = 63 nM), which are considered to be valid molecular targets in the diagnostics and therapy of various autoimmune disorders and cancers. Here we synthesized 25 analogues of SPX and analyzed the role of each amino acid in SPX using alanine scanning to study its structure-function relationships. All synthetic analogues showed similar disulfide bond pairings and secondary structures as native SPX. Alanine replacements at Lys 23 , Asn 26 , and Lys 30 resulted in loss of activity against Kv1.3 potassium channels, whereas replacements at Arg 7 , Met 14 , Lys 27 , and Tyr 32 also largely reduced inhibitory activity. These results suggest that the side chains of these amino acids in SPX play an important role in its interaction with Kv1.3 channels. In particular, Lys 23 appears to be a key residue that underpins Kv1.3 channel inhibition. Of these seven amino acid residues, four are basic amino acids, suggesting that the positive electrostatic potential on the surface of SPX is likely required for high affinity interaction with Kv1.3 channels. This study provides insight into the structure-function relationships of SPX with implications for the rational design of new lead compounds targeting potassium channels with high potency.

Original languageEnglish
Pages (from-to)2927-2935
Number of pages9
JournalBiochemistry
Volume55
Issue number21
DOIs
Publication statusPublished - May 31 2016

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Scorpions
Kv1.3 Potassium Channel
Potassium Channels
Alanine
Scorpion Venoms
Catalytic Domain
Scanning
Amino Acids
Disulfides
Lead compounds
Voltage-Gated Potassium Channels
Basic Amino Acids
Peptides
Neurotoxins
Static Electricity
Electrostatics
Neoplasms
Therapeutics

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Peigneur, S., Yamaguchi, Y., Kawano, C., Nose, T., Nirthanan, S., Gopalakrishnakone, P., ... Sato, K. (2016). Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning. Biochemistry, 55(21), 2927-2935. https://doi.org/10.1021/acs.biochem.6b00139

Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning. / Peigneur, Steve; Yamaguchi, Yoko; Kawano, Chihiro; Nose, Takeru; Nirthanan, Selvanayagam; Gopalakrishnakone, Ponnampalam; Tytgat, Jan; Sato, Kazuki.

In: Biochemistry, Vol. 55, No. 21, 31.05.2016, p. 2927-2935.

Research output: Contribution to journalArticle

Peigneur, S, Yamaguchi, Y, Kawano, C, Nose, T, Nirthanan, S, Gopalakrishnakone, P, Tytgat, J & Sato, K 2016, 'Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning', Biochemistry, vol. 55, no. 21, pp. 2927-2935. https://doi.org/10.1021/acs.biochem.6b00139
Peigneur, Steve ; Yamaguchi, Yoko ; Kawano, Chihiro ; Nose, Takeru ; Nirthanan, Selvanayagam ; Gopalakrishnakone, Ponnampalam ; Tytgat, Jan ; Sato, Kazuki. / Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning. In: Biochemistry. 2016 ; Vol. 55, No. 21. pp. 2927-2935.
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