中等分辨率的白鲢鱼胰岛素的晶体结构

胰岛素结构和功能研究的一条重要途径是分析来源于不同种属的胰岛素的结构。基于用分子置换法获得的白鲢鱼胰岛素正交晶体结构模型,使用2.8分辨率衍射强度数据和约束参数最小二乘法,对处于不同结晶环境的6个白鲢鱼胰岛素分子进行了晶体学修正。胰岛素结构的比较研究表明,6个白鲢鱼胰岛素分子具有非常相似但不等同的三维结构,它们的结构类似于已知的三方二锌猪胰岛素结构,但某些局部构象有明显的差异。     

白鲢鱼胰岛素的晶体学研究

本实验获得了白鲢鱼胰岛素的单晶体并收集了2.8A分辨率的强度数据.确定晶体所属空间群为 P2_12_12_1,晶胞参数是a=96.73(8)A,b=57.74(7)A,c=53.88(9)A.每个不对称单位含有6个胰岛素分子.用旋转函数法揭示出非晶体学三重轴和二重轴的取向,并说明了白鲢鱼胰岛素具有与三方二锌猪胰岛素相似的空间结构和聚合状态.本文讨论了一级结构的变化对胰岛素的结晶行为和堆积方式的影响。     

STRUCTURE OF (Trp)~(B1)-INSULIN AT 2RESOLUTION

The rhombohedral crystal structure of [Trp]~(B1)-insulin has been refined, using data to 2 and atomic coordinates of 2-zinc porcine insulin as starting model, and through the use of the restrained least-squares method, to an R value of 0.24. The result of refinement shows that in comparison with the 2-zinc insulin structure, some changes in local conformation occur, and are asymmetric for the two independent molecules related by a local two-fold axis. The obvious conformational changes are found to be in molecule 1, at its B-chain N-terminus and A13-residue region.     

THE CRYSTAL STRUCTURE OF SILVER CARP INSULIN AT MEDIUM RESOLUTION

It is an important way of surveying the structure-functionrelationship of insulin tostudy insulins from different species. Based on the structure model of an orthorhombic crys-tal obtained by the molecular replacement method, the crystallographic refinement of a hex-amer of silver carp insulin in an asymmetric unit has been carried out with 2.8A resolutiondata using the restrained least- squares method. The comparisons of insulin structures haveshown that the six silver carp insulin molecules have very similar but not identical three- di-mensional structures which are similar to the known 2Zn pig insulin structure but remarka-bly different in some local conformations.     

CRYSTALLOGRAPHIC STUDIES OF SILVER CARP INSULIN

Silver carp insulin crystallizes in space group P2_12_12_1 with cell dimensions a=96.73(8), b=57.74(7), and c=53.88(9). There are six molecules in an asymmetric unit. The orientations of non-crystallographic three- and two-fold axes have been worked out by the rotation function method and the results indicate that silver carp insulin has a spatial structure and a mode of aggregation similar to that of the rhombohedral 2-Zn pig insulin, though the crystal packings are different. In the present paper, we discuss the influence of the changes in sequence of insulin upon crystallization behaviour and packing of molecules     

金属硫蛋白溶液聚合状态的研究

通过动态光散射实验首次证明了兔肝金属硫蛋白亚型 和 在不同的缓冲体系中不仅仅是以二聚体的形式 ,而且是以多种聚合形式存在[1] .深入考察金属硫蛋白在溶液中的聚合形式对于研究金属硫蛋白的结构和功能都具有非常重要的意义 .我们通过计算机模拟 [1] 比较系统地研究了各种因素对金属硫蛋白聚合的影响 .结果表明 ,在溶液聚合的分子识别过程中可由多种因素共同调控金属硫蛋白 ,这些因素主要包括静电相互作用、疏水性相互作用和溶液中阴阳离子等 .通过这些因素的综合分析 ,首次对兔肝金属硫蛋白在溶液中多种聚合形式的形成机制及相应的分子…     

[Trp]~(B1)胰岛素的2分辨率结构

用2分辨率强度数据,以三方二锌猪胰岛素分子的原子坐标为初始模型,应用约束最小二乘方法对[Trp]~(B1)猪胰岛素结构进行了晶体学修正,R值下降到0.24。同三方二锌胰岛素相比,原来呈近似二重对称的两个独立分子的结构发生了不对称的变化。明显的构象变化产生在分子IB链N端和邻近残基A13的区域。     

STRUCTURE DETERMINATION OF THE SILVER CARP INSULIN CRYSTAL

After rotation search of an orthorhombic crystal form of Silver Carp insulin, based on the known porcine 2-Zn insulin structure, the Silver Carp insulin molecules were positioned in the unit cell by applying the translation function and R-factor search methods. The packing of the molecules in the cell is reasonably good. A preliminary refinement of this model at 3.5 resolution has been carried out through the use of restrained least-squares method. The segments of polypeptide chain, which were not involved in the refinement, could be visible in the electron density map calculated using the refined atomic parameters.     

白鲢鱼胰岛素的晶体结构测定

本文继用旋转函数方法对白鲢鱼胰岛素分子在P2_12_12_1晶胞中的取向分析之后,以已知的二锌猪胰岛素分子为模型,应用平移函数及R因子搜索方法,确定了白鲢鱼胰岛素六聚体在晶胞中的位置。在这样得到的模型晶胞中,分子的堆积合理。利用现有的3.5衍射数据,对该模型进行了初步的约束参数最小二乘修正。用修正过的原子参数算得的电子密度图上,未投入修正的多肽链片段有相应的表现。     

微重力下的蛋白质晶体生长

空间微重力环境是研究复杂的蛋白质结晶过程和生长高质量蛋白质晶体的理想地方。于1992年8月应用国内研制的装置,在返回式卫星FSW-2上完成了空间蛋白质晶体生长实验。有6种蛋白质在空间长出了晶体,其中蛇毒酸性磷脂酶A_2和鸡蛋清溶菌酶的晶体明显优于地面对照实验长出的晶体,表明空间的微重力利于改进蛋白质晶体的大小、完整性、形态及内部有序性。