The structure and heavy-metal-ion-binding sites of horse spleen apoferritin.
The structure and heavy-metal-ion-binding sites of horse spleen apoferritin.
复制标题
马脾去铁铁蛋白的结构和重金属离子结合位点。
DOI：
10.1042/bst0080654
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发表时间：
1980
影响因子：
3.9
通讯作者：
P. Harrison
中科院分区：
文献类型：
--
作者：
G. Clegg;R. Stansfield;P. Bourne;P. Harrison
马脾Apoferritin在面心立方空间群F432中结晶，a=18.4 nm(184a)，计算出0.28 nm(2.8 A)分辨率的电子密度图(Banyard等人，1978)。该分子是由24个等效亚单位按432对称排列而成的近似球形的L壳层[外径13.0 nm(130A)，内径8.0 nm(80A)]。这个大的腔体能够存储多达4500个Fe(II1)原子，作为一种微晶无机成分，其组成近似(FeOOH)，(FeO-OPO，H，)。亚基几乎平行于三重轴，垂直于两重轴，呈圆柱形，包含四个平行(或反平行)圆柱轴的螺旋，约占一级结构的三分之二。此外，在亚基的外表面上有一个很长的环，它似乎形成了一条反平行/？褶皱的短片，该环来自与对称相关的两个相邻的环。这些二级结构区域之间的联系尚不清楚。在Richards‘s比较器(Richards，1968)中建立了亚基的多肽骨架，并测量了a-碳和羰基氧的配位。其余主干原子和/？-碳原子的位置已经计算并规则化为标准几何形状(Dodson等人，1976)。希望包含从这些位置得到的位相信息将提供改进的电子密度
An electron-density map at 0.28 nm (2.8 A) resolution has been calculated for horse spleen apoferritin crystallized in the face-centred cubic space group F432, with a= 18.4 nm (184A)(Banyard et al., 1978). The molecule is a nearly spherical shell [outside and inside diameters respectively 13.0 nm (130A) and 8.0 nm (80A) l formed from 24 equivalent subunits arranged in 432 symmetry. The large cavity is capable of storing up to 4500 Fe (II1) atoms as a microcrystalline inorganic component of approximate composition (FeOOH),(FeO-OPO, H,). The subunits, which lie nearly parallel to threefold and perpendicular to twofold axes, have a cylindrical shape and contain four helices running parallel (or anti-parallel) to the cylinder axis and accounting for about two-thirds of the primary structure. In addition there is a long loop, running over the outside surface of the subunit, that appears to form a short piece of anti-parallel/?-pleated sheet with the loop from its twofoldsymmetry-related neighbour. Connectivities between these regions of secondary structure are not yet clear. The polypeptide backbone of a subunit has been built in a Richards's comparator (Richards, 1968), and a-carbon and carbonyl oxygen co-ordinates have been measured. Positions of the remaining backbone atoms and/?-carbon atoms have been calculated and regularized to standard geometry (Dodson et al., 1976). It is hoped that inclusion of phase information derived from these positions will provide improved electron-density