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. 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.
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.
- Zhang N, Li M, Chen X, Wang Y, Wu G, Hu G, Wu H (June 2004). "Solution structure of BmKK2, a new potassium channel blocker from the venom of chinese scorpion Buthus martensi Karsch". Proteins 55 (4): 835â45. doi:10.1002/prot.20117. PMID 15146482.
- Li MH, Zhang NX, Chen XQ, Wu G, Wu H, Hu GY (June 2004). "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): 895â900. doi:10.1016/j.toxicon.2003.11.028. PMID 15208022.