Molecular dynamism of Fe-S cluster biosynthesis implicated by the structure of the SufC(2)-SufD(2) complex.
Molecular dynamism of Fe-S cluster biosynthesis implicated by the structure of the SufC(2)-SufD(2) complex.
复制标题
SufC(2)-SufD(2) 复合物的结构涉及 Fe-S 簇生物合成的分子动力学。
DOI：
10.1016/j.jmb.2009.01.054
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发表时间：
2009
影响因子：
5.6
通讯作者：
Fukuyama,Keiichi
中科院分区：
文献类型：
--
作者：
Wada,Kei;Sumi,Norika;Nagai,Rina;Iwasaki,Kenji;Sato,Takayuki;Suzuki,Kei;Hasegawa,Yuko;Kitaoka,Shintaro;Minami,Yoshiko;Outten,FWayne;Takahashi,Yasuhiro;Fukuyama,Keiichi
铁硫蛋白（Fe-S）的成熟是通过SUF机制在许多真细菌和古细菌以及真核叶绿体中实现的。这种机制在大肠杆菌中由sufABCDSE操纵子编码，其中三个Suf组分SufB、SufC和SufD形成复合物，并似乎为Fe-S簇组装提供中间位点。在这里，我们报告的四级结构的SufC 2-SufD 2复合物，其中SufC是绑定到C-末端结构域的SufD。与单体结构的SufC的比较显示活性位点残基的构象变化：SufC成为主管ATP结合和水解后，与SufD协会。两个SufC亚基在空间上分离的SufC 2-SufD 2复合物，而在溶液中的交联实验表明，两个SufC分子相互关联的Mg 2+和ATP的存在下。SufC的这种二聚体形成可能导致SufC 2-SufD 2复合物的总体结构变化。此外，SufD的遗传分析揭示了一个必不可少的组氨酸残基埋在二聚体界面内，这表明构象变化可能会暴露这个关键的残基。这些发现，连同生化表征的SufB-SufC-SufD复杂，使我们提出了一个模型的铁-S簇生物合成的复杂。
Maturation of iron–sulfur (Fe–S) proteins is achieved by the SUF machinery in a wide number of eubacteria and archaea, as well as eukaryotic chloroplasts. This machinery is encoded in Escherichia coli by the sufABCDSE operon, where three Suf components, SufB, SufC, and SufD, form a complex and appear to provide an intermediary site for the Fe–S cluster assembly. Here, we report the quaternary structure of the SufC2–SufD2complex in which SufC is bound to the C-terminal domain of SufD. Comparison with the monomeric structure of SufC revealed conformational change of the active-site residues: SufC becomes competent for ATP binding and hydrolysis upon association with SufD. The two SufC subunits were spatially separated in the SufC2–SufD2complex, whereas cross-linking experiments in solution have indicated that two SufC molecules associate with each other in the presence of Mg2+and ATP. Such dimer formation of SufC may lead to a gross structural change of the SufC2–SufD2complex. Furthermore, genetic analysis of SufD revealed an essential histidine residue buried inside the dimer interface, suggesting that conformational change may expose this crucial residue. These findings, together with biochemical characterization of the SufB–SufC–SufD complex, have led us to propose a model for the Fe–S cluster biosynthesis in the complex.