BmKK2 toxin explained

In molecular biology, the BmKK2 toxins are a family of scorpion toxins. They belong to the scorpion toxin subfamily alpha-KTx 14. They include a novel short-chain peptide from the Asian scorpion Mesobuthus martensii Karsch, a potassium channel blocker composed of 31 amino acid residues.^[1] The peptide adopts a classical alpha/beta-scaffold for alpha-KTxs. BmKK2 selectively inhibits the delayed rectifier K+ current, but does not affect the fast transient K+ current.^[2]

In comparison with typical short-chain scorpion toxins (e.g., CTX and NTX), the alpha helix is shorter and the beta-sheet element is smaller (each strand consists of only two residues). There is an alpha-mode binding between the toxin and the channels. It has a lower activity towards Kv channels and it is predicted that it may prefer a type of SK channel with a narrower entryway as a specific receptor.^[1]

Notes and References

1. Zhang N, Li M, Chen X, Wang Y, Wu G, Hu G, Wu H . Solution structure of BmKK2, a new potassium channel blocker from the venom of chinese scorpion Buthus martensi Karsch . Proteins . 55 . 4 . 835–45 . June 2004 . 15146482 . 10.1002/prot.20117 . free .
2. Li MH, Zhang NX, Chen XQ, Wu G, Wu H, Hu GY . Purification and pharmacological characterization of BmKK2 (alpha-KTx 14.2), a novel potassium channel-blocking peptide, from the venom of Asian scorpion Buthus martensi Karsch . Toxicon . 43 . 8 . 895–900 . June 2004 . 15208022 . 10.1016/j.toxicon.2003.11.028 .