Solution Structure of BmP02, a New Potassium Channel Blocker from the Venom of the Chinese Scorpion Buthus martensi Karsch
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- 作者：Yingqi Xu ; Jihui Wu ; Jiming Pei ; Yunyu Shi ; Yonghua Ji ; and Qingchun Tong
- 刊名：Biochemistry
- 出版年：2000
- 出版时间：November 14, 2000
- 年：2000
- 卷：39
- 期：45
- 页码：13669 - 13675
- 全文大小：263K
- 年卷期：v.39,no.45(November 14, 2000)
- ISSN：1520-4995
文摘
BmP02 is a 28-amino acid residue peptide purified from the venom of the Chinese scorpionButhus martensi Karsch, which had been demonstrated to be a weak blocker of apamin-sensitive calcium-activated potassium channels. Two-dimensional NMR spectroscopy techniques were used to determinethe solution structure of BmP02. The results show that BmP02 formed a 
ges/gifchars/alpha.gif" BORDER=0>/ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> scorpion fold, the typicalthree-dimensional structure adopted by most short chain scorpion toxins whose structures have beendetermined. However, in BmP02 this ges/gifchars/alpha.gif" BORDER=0>/ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> fold was largely distorted. The ges/gifchars/alpha.gif" BORDER=0>-helix was shortened to onlyone turn, and the loop connecting the helix to the first ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-strand exhibited conformational heterogeneity.The instability of BmP02 could be attributed to a proline at position 17, which is usually a glycine.Because the residue at this position makes intense contact with the ges/gifchars/alpha.gif" BORDER=0>-helix, it was supposed that thebulky side chain of proline had pushed the helix away from the ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-sheet. This had a significant influenceon the structure and function of BmP02. The ges/gifchars/alpha.gif" BORDER=0>-helix rotated by about 40ges/entities/deg.gif"> to avoid Pro17 while formingtwo disulfides with the second ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-strand. The rotation further caused both ends of the helix to be unwounddue to covalent restrictions. According to its structure, BmP02 was supposed to interact with its target viathe side chains of Lys11 and Lys13.