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8.B.10 The Psalmotoxin-1 (PcTx1) Family

Psalmotoxin-1 is spider toxin that is selective and high affinity inhibitor of ASIC1a. PcTx1 inhibits ASIC1a homomers with an affinity of 0.7 nM without any effect on ASIC1a containing heteromers. It thus helped to characterize ASIC1a homomeric channels in peripheric and central neurons. PcTx1 acts as a gating modifier since it shifts the channel from the resting to an inactivated state by increasing its affinity for H(+) (Diochot et al., 2007). PcTx1 homologous to cystine knot toxin of Chilobrachys jingzhao (38% identity). The 3-d structure of PcTx1 has been solved by NMR (1LMM_A; Escoubas et al. 2003). The binding of PcTx1 to ASIC1a channels (1.A.6) depends on the β-sheet and β-turn linking and residues known to be implicated in channel recognition of other inhibitory cystine knot (ICK) toxins.

References associated with 8.B.10 family:

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Yu, H., L. Yang, L. Liu, X. Zhao, and X. Huang. (2017). Molecular dynamics simulations investigate the Mechanism of Psalmotoxin 1 regulating gating process of an Acid-sensing ion channel 1a at pH 5.5. J Biomol Struct Dyn 1-21. [Epub: Ahead of Print] 28768463