8.B.26 The Scorpion Toxin, Scoloptoxin (Scoloptoxin) Family The Scoloptoxin family includes a number of peptide/protein toxins of vaious sized that bind to and inhibit various Na⁺ and K⁺ channels of the VIC superfamily (1.A.1). For example, κ-scoloptoxin, Ssm1a, inhibits voltage-gated potassium channel currents in DRG neurons with an IC₅₀ of 44.2 nM and shows signs of neurotoxicity including twitching, paralysis, and body contractions (Yang et al. 2012), and the 47 aa centipede toxin, Ssd609, inhibits K⁺ currents by binding to KCNE1 (8.A.10.1.1), a single-span transmembrane auxiliary protein that modulates the voltage-gated potassium channel KCNQ1 (TC# 1.A.1.15.1 and 1.A.1.15.6). The KCNQ1/KCNE1 complex in cardiomyocytes exhibited slow activated potassium (Iks) currents (Sun et al. 2015). Another centipede toxin, SsmTx-I acts as a simple inhibitor or channel blocker rather than a gating modifier of at least 9 channels including Kv2.1 (TC# 1.A.1.2.11) (Chen et al. 2014). The high resolution structures of several of these toxins are known.
References:
Chen, M., J. Li, F. Zhang, and Z. Liu. (2014). Isolation and characterization of SsmTx-I, a Specific Kv2.1 blocker from the venom of the centipede Scolopendra Subspinipes Mutilans L. Koch. J Pept Sci 20: 159-164.
Sun, P., F. Wu, M. Wen, X. Yang, C. Wang, Y. Li, S. He, L. Zhang, Y. Zhang, and C. Tian. (2015). A distinct three-helix centipede toxin SSD609 inhibits Iks channels by interacting with the KCNE1 auxiliary subunit. Sci Rep 5: 13399.
Yang, S., Z. Liu, Y. Xiao, Y. Li, M. Rong, S. Liang, Z. Zhang, H. Yu, G.F. King, and R. Lai. (2012). Chemical punch packed in venoms makes centipedes excellent predators. Mol. Cell Proteomics 11: 640-650.
Examples:
TC#	Name	Organismal Type	Example
8.B.26.1.1	*κ-scoloptoxin of 74 aas. Inhibits K⁺ currents selectively (Yang et al.* 2012).**		κ-Scoloptoxin of Scolopendra mutilans (Chinese red-headed centipede) (Scolopendra subspinipes mutilans)

8.B.26.1.2	Kappa-SLPTX-Ssm1c toxin of 73 aas that inhibits voltage-gated potassium channels.		kappa toxin Ssm1c of Scolopendra mutilans (Chinese red-headed centipede) (Scolopendra subspinipes mutilans)

8.B.26.1.3	Mu-SLPTx3-ssm6a is a 46 aas fragment of protein P0DL36. The 3D structure has been solved (PDB# 2MUN). The full length protein sequence is available under TC# 8.B.26.1.4.		SSM61 of Scolopendra mutilans

8.B.26.1.4	Mu-SLPTx3-Ssm6a of 112 aas (full length version). The full length protein contains a signal peptide and a propeptide that are removed postranslationally, and the final protein (the short version) is of 46 aas and corresponds to the C-terminal segment of the full length protein. Its solution structure is available (PDB# 2MUN) but this peptide lacks a RefSeq or UniProt accession # but is included in TCDB under TC# 8.B.26.1.3.		SSM61 of Scolopendra mutilans

8.B.26.1.5	Uncharacterized protein of 105 aas		UP of Amphibalanus amphitrite

8.B.26.1.6	Kappa-scoloptoxin-Ssm1d; Short=Kappa-SLPTX-Ssm1d of 75 aas	Ssm1d of Scolopendra mutilans	κ-scoloptonxin of Scolopendra mutilans (Chinese red-headed centipede)

8.B.26.1.7	Uncharacteerized protein of 69 aas and 1 N-terminal TMS		*UP of Neodiprion lecontei* (redheaded pine sawfly)**

Examples:
TC#	Name	Organismal Type	Example