CRYSTALLIZATION AND STRUCTURE DETERMINATION TO 2.5-A RESOLUTION OF THE OXIDIZED [FE2-S2] FERREDOXIN ISOLATED FROM ANABAENA-7120
CRYSTALLIZATION AND STRUCTURE DETERMINATION TO 2.5-A RESOLUTION OF THE OXIDIZED [FE2-S2] FERREDOXIN ISOLATED FROM ANABAENA-7120
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DOI：
10.1021/bi00231a003
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发表时间：
1991-04-30
期刊：
影响因子：
2.9
通讯作者：
HOLDEN, HM
中科院分区：
文献类型：
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作者：
RYPNIEWSKI, WR;BREITER, DR;HOLDEN, HM
从蓝藻鱼腥藻种菌株PCC 7120中分离的[2Fe-2S]铁氧还蛋白的氧化形式的分子结构已经通过X射线衍射分析确定为2.5埃的标称分辨率，并精确到18.7%的晶体学R因子。本研究中使用的晶体属于空间群P2（1）2（1）2（1），晶胞尺寸为a = 37.42埃，B = 38.12埃，c = 147.12埃，非对称单元中有两个分子。 这种铁氧还蛋白的三维结构的解决方法，结合X射线数据从一个同晶重原子衍生物与非晶体对称性平均和溶剂平坦。 与其他植物型[2Fe-2S]铁氧还蛋白一样，铁-硫簇位于分子的外缘，铁与无机硫和蛋白质半胱氨酸残基提供的硫形成四面体配位。 主要的二级结构元件包括四股β-折叠片和三个α-螺旋区域。
The molecular structure of the oxidized form of the [2Fe-2S] ferredoxin isolated from the cyanobacterium Anabaena species strain PCC 7120 has been determined by X-ray diffraction analysis to a nominal resolution of 2.5 angstrom and refined to a crystallographic R factor of 18.7%. Crystals used in this investigation belong to the space group P2(1)2(1)2(1) with unit cell dimensions of a = 37.42 angstrom, b = 38.12 angstrom, and c = 147.12 angstrom and two molecules in the asymmetric unit. The three-dimensional structure of this ferredoxin was solved by a method that combined X-ray data from one isomorphous heavy-atom derivative with noncrystallographic symmetry averaging and solvent flattening. As in other plant-type [2Fe-2S] ferredoxins, the iron-sulfur cluster is located toward the outer edge of the molecule, and the irons are tetrahedrally coordinated by both inorganic sulfurs and sulfurs provided by protein cysteine residues. The main secondary structural elements include four strands of beta-pleated sheet and three alpha-helical regions.