摘要
毒素BmKⅢ是从马氏钳蝎毒液中提取的一个毒性最强的α类神经毒素.从该组分的水溶液和重水溶液拉曼光谱(450—1750cm^(-1))的分析,可以确定其分子的二级结构中以β折迭为主,有较大量的β回折结构和一定数量的无规卷曲,α螺旋不多.采用Lippert提出的线性方程组法计算得到分子中含β折迭41.7%,α螺旋17.7%,无规卷曲40.6%.分子中的四对二硫键均为gauche—gauche—gauche构型.侧链芳香性氨基酸残基大多数暴露在分子表面.文中对有有关毒素构象方面的问题进行了讨论.
Toxin Bmk-Ⅲ , a mammal neurotoxic protein of the type, is most poisonous component isolated from the venom of Chinese scorpion, Buthus martensi Karsch. Raman spectra (450-1750cm-1 region) of the toxin both in H2O and D2O were investigated. From the vibrational spectra, it can be concluted that the polypeptide backbone of BmK-Ⅲ consists of mixture of the different structure, with predominance of β-sheet, followed by random coil and β-turn, with a few of α-helix. The secondary structure contents of BmK-Ⅲ were calculated with the method developed by Lippert et al.- 41.7% of amino acid residues is in β-sheet, 17.7% in -helix and 40.6% in random coil. The four disulfide bridges assume the gauche-gauche-gauche conformation of the CCSSCC fragments. Most of aromatic residues are exposed on the surface. Some discussions have been made in relation to this method and relationship of structure and function of toxin BmK-Ⅲ.
出处
《生物物理学报》
CAS
CSCD
北大核心
1991年第2期121-125,共5页
Acta Biophysica Sinica
基金
国家自然科学基金
