Atomic resolution (0.94 Å) structure of Clostridium acidurici ferredoxin.: Detailed geometry of [4Fe-4S] clusters in a protein
Atomic resolution (0.94 Å) structure of Clostridium acidurici ferredoxin.: Detailed geometry of [4Fe-4S] clusters in a protein
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DOI：
10.1021/bi972155y
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发表时间：
1997-12-23
期刊：
影响因子：
2.9
通讯作者：
Moulis, JM
中科院分区：
文献类型：
--
作者：
Dauter, Z;Wilson, KS;Moulis, JM
利用100 K下记录的X射线衍射数据，获得了耐酸梭菌（Clostridiumacidurici）2[4Fe-4S]铁氧还蛋白的晶体结构。该模型与各向异性表示的原子位移参数的所有非氢原子和氢骑在他们的母原子进行了改进。立体化学的限制施加到蛋白质链，但不铁-硫簇。所有数据的最终R因子为10.03%。最后的最小二乘矩阵的反演允许直接估计单个参数的误差。蛋白质主链原子位置的估计误差低于0.02埃，较重的[4Fe-4S]原子簇的估计误差约为0.003埃。这两个簇的立体化学之间的显着差异和它们两者从理想的T-d四面体对称性的扭曲可以详细定义在这个精度水平。替代构象的区域不仅包括蛋白质侧链，还包括主链的两个区域。一个这样的区域是残基25-29的环，其在室温结构中高度无序。
The crystal structure of the 2[4Fe-4S] ferredoxin from Clostridium acidurici has been solved using X-ray diffraction data extending to atomic resolution, 0.94 Angstrom, recorded at 100 K. The model was refined with anisotropic representation of atomic displacement parameters for all non-hydrogen atoms and with hydrogens riding on their parent atoms. Stereochemical restraints were applied to the protein chain but not to the iron-sulfur clusters. The final R factor is 10.03 % for all data. Inversion of the final least-squares matrix allowed direct estimation of the errors of individual parameters. The estimated errors in positions for protein main chain atoms are below 0.02 Angstrom and about 0.003 Angstrom for the heavier [4Fe-4S] cluster atoms. Significant differences between the stereochemistry of the two clusters and distortion of both of them from ideal T-d tetrahedral symmetry can be defined in detail at this level of accuracy. Regions of alternative conformations include not only protein side chains but also two regions of the main chain. One such region is the loop of residues 25-29, which was highly disordered in the room temperature structure.