1. Solution structure of BmBKTx1, a new BKCa1 channel blocker from the Chinese scorpion Buthus martensi Karsch
- Author
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Zheng, Cai, Chenqi, Xu, Yingqi, Xu, Wuyuan, Lu, Cheng-wu, Chi, Yunyu, Shi, and Jihui, Wu
- Subjects
Sequence Homology, Amino Acid ,Molecular Sequence Data ,Scorpion Venoms ,Hydrogen Bonding ,Stereoisomerism ,Crystallography, X-Ray ,Protein Structure, Secondary ,Solutions ,Potassium Channels, Calcium-Activated ,Potassium Channels, Voltage-Gated ,Animals ,Amino Acid Sequence ,Nuclear Magnetic Resonance, Biomolecular ,Conserved Sequence - Abstract
BmBKTx1 is a 31-amino acid peptide identified from the venom of the Chinese scorpion Buthus martensi Karsch, blocking high-conductance calcium-activated potassium channels. Sequence homology analysis indicates that BmBKTx1 is a new subfamily of short-chain alpha-KTx toxins of the potassium channel, which we term alpha-KTx19. Synthetic BmBKTx1 was prepared by using solid-phase peptide synthesis. Two-dimensional NMR spectroscopy techniques were used to determine the solution structure of BmBKTx1. The results show that the BmBKTx1 forms a typical cysteine-stabilized alpha/beta scaffold adopted by most short-chain scorpion toxins. The structure of BmBKTx1 consists of a two-stranded antiparallel beta-sheet (residues 20-29) and an alpha-helix (residues 5-15). The three-dimensional structure of BmBKTx1 was also compared with those of two function-related scorpion toxins, charybdotoxin (ChTx) and BmTx1, and their structural and functional implications are discussed.
- Published
- 2004