Solution structure of the oxidized Fe7S8 ferredoxin from the thermophilic bacterium Bacillus schlegelii by 1H NMR spectroscopy
Solution structure of the oxidized Fe7S8 ferredoxin from the thermophilic bacterium Bacillus schlegelii by 1H NMR spectroscopy
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DOI：
10.1021/bi972818b
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发表时间：
1998-07-07
期刊：
影响因子：
2.9
通讯作者：
Rosato, A
中科院分区：
文献类型：
--
作者：
Aono, S;Bentrop, D;Rosato, A
用核磁共振氢谱测定了施氏芽孢杆菌的顺磁性七铁氧化还蛋白氧化产物的溶液结构。该蛋白质含有77个氨基酸，具有耐热性。在理论上预期的所有质子共振中，有72个残基和79%已经被指定。用DYANA程序通过扭角动力学计算确定了半胱氨酸的结构，使用了966个有意义的NOE(总共1305个)、氢键约束和核磁共振得出的二面角约束来连接半胱氨酸，并利用结晶学信息建立了两个簇。然后，将约束能量最小化和约束分子动力学应用于该家族的每个构象。最终的20个结构家族的RMSD值来自主干原子的平均结构0.68埃，所有重原子的平均结构1.16埃。通过将目前的结构与不太稳定的棕色固氮菌铁氧还蛋白I的结构进行比较，讨论了该铁氧还蛋白对热稳定性的贡献，后者是细菌七铁铁还蛋白的唯一另一种结构。研究表明，N-端和C-端之间的疏水相互作用和氢键网络以及大量的盐桥对稳定性有贡献。
The solution structure of the paramagnetic seven-iron ferredoxin from Bacillus schlegelii in its oxidized form has been determined by H-1 NMR. The protein, which contains 77 amino acids, is thermostable. Seventy-two residues and 79% of all theoretically expected proton resonances have been assigned. The structure has been determined through torsion angle dynamics calculations with the program DYANA, using 966 meaningful NOEs (from a total of 1305), hydrogen bond constraints, and NMR derived dihedral angle constraints for the cluster ligating cysteines, and by using crystallographic information to build up the two clusters. Afterwards, restrained energy minimization and restrained molecular dynamics were applied to each conformer of the family. The final family of 20 structures has RMSD values from the mean structure of 0.68 Angstrom for the backbone atoms and of 1.16 Angstrom for all heavy atoms. The contributions to the thermal stability of the B. schlegelii ferredoxin are discussed by comparing the present structure to that of the less stable Azotobacter vinelandii ferredoxin I which is the only other available structure of a bacterial seven-iron ferredoxin. It is proposed that the hydrophobic interactions and the hydrogen bond network linking the N-terminus and the C-terminus together and a high number of salt bridges contribute to the stability.