Tetrameric structure of thermostable direct hemolysin from Vibrio parahaemolyticus revealed by ultracentrifugation, small-angle X-ray scattering and electron microscopy
Tetrameric structure of thermostable direct hemolysin from Vibrio parahaemolyticus revealed by ultracentrifugation, small-angle X-ray scattering and electron microscopy
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DOI：
10.1016/j.jmb.2006.09.070
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发表时间：
2007-01-05
影响因子：
5.6
通讯作者：
Yanagihara, Itaru
中科院分区：
文献类型：
--
作者：
Hamada, Daizo;Higurashi, Takashi;Yanagihara, Itaru
耐热直接溶血素（TDH）是副溶血性弧菌的主要毒力因子。通过小角X射线散射（SAXS）、超离心和透射电子显微镜对TDH的构象性质进行了表征。沉降平衡和速度的研究表明，蛋白质是四聚体在水溶液中。从SAXS数据得到的Guinier图提供了29.0埃的回转半径。具有从SAXS数据导出的对距离分布函数的肩部的细长图案表明存在具有最大直径为98埃的各向异性形状的分子。负染色的TDH寡聚体的电子显微镜图像分析显示存在。的C-4对称粒子的边长和对角线长度分别为65埃和80埃。形状重建进行了从头计算使用SAXS数据与C4对称近似。这些结果表明，四聚体TDH呈现扁球形结构。从头算模型预测的流体动力学参数与实验值略有不同，这表明存在柔性段。
The thermostable direct hemolysin (TDH) is a major virulence factor of Vibrio parahaemolyticus. We have characterized the conformational properties of TDH by small-angle X-ray scattering (SAXS), ultracentrifugation and transmission electron microscopy. Sedimentation equilibrium and velocity studies revealed that the protein is tetrameric in aqueous solvents. The Guinier plot derived from SAXS data provided a radius of gyration of 29.0 angstrom. The elongated pattern with a shoulder of a pair distance distribution function derived from SAXS data suggested the presence of molecules with an anisotropic shape having a maximum diameter of 98 angstrom. Electron microscopic image analysis of the negatively stained TDH oligomer showed the presence. of C-4 symmetric particles with edge and diagonal lengths of 65 angstrom and 80 angstrom, respectively. Shape reconstruction was carried out by ab initio calculations using the SAXS data with a C4 symmetric approximation. These results suggested that the tetrameric TDH assumes an oblate structure. The hydrodynamic parameters predicted from the ab initio model differed slightly from the experimental values, suggesting the presence of flexible segments.