Site-directed mutagenesis of Azotobacter vinelandii ferredoxin I: cysteine ligation of the [4Fe-4S] cluster with protein rearrangement is preferred over serine ligation.
Site-directed mutagenesis of Azotobacter vinelandii ferredoxin I: cysteine ligation of the [4Fe-4S] cluster with protein rearrangement is preferred over serine ligation.
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维氏固氮菌铁氧还蛋白 I 的定点诱变：[4Fe-4S]簇的半胱氨酸连接与蛋白质重排优于丝氨酸连接。
DOI：
10.1073/pnas.92.22.10064
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发表时间：
1995
影响因子：
11.1
通讯作者：
Burgess,BK
中科院分区：
文献类型：
--
作者：
Shen,B;Jollie,DR;Diller,TC;Stout,CD;Stephens,PJ;Burgess,BK
棕色固氮菌铁氧还蛋白I的[4Fe-4S]簇在位置39-45处从Cys-Xaa-Xaa-Cys-Xaa-Xaa-Cys序列接收其四个配体中的三个，而第四个配体Cys 20由该序列的远端部分提供。以前我们报道过Cys 20定点突变为Ala（C20 A蛋白）导致形成一个新的[4Fe-4S]簇，该簇从天然结构中的游离半胱氨酸Cys 24获得其第四个配体。这种配体交换需要显著的蛋白质重排。在这里，我们报告的转换Cys 20丝氨酸（C20 S蛋白），这使蛋白质的机会，要么保留天然结构，并使用Ser 20 O γ作为配体或重新排列和使用Cys 24。X射线晶体学表明，该簇不使用Ser 20 O γ作为配体;相反，它重排使用Cys 24。在C20 S蛋白中，[4Fe-4S]簇相对于C20 A或天然蛋白具有改变的稳定性和氧化还原性质。
The [4Fe-4S] cluster of Azotobacter vinelandii ferredoxin I receives three of its four ligands from a Cys-Xaa-Xaa-Cys-Xaa-Xaa-Cys sequence at positions 39-45 while the fourth ligand, Cys20, is provided by a distal portion of the sequence. Previously we reported that the site-directed mutation of Cys20 to Ala (C20A protein) resulted in the formation of a new [4Fe-4S] cluster that obtained its fourth ligand from Cys24, a free cysteine in the native structure. That ligand exchange required significant protein rearrangement. Here we report the conversion of Cys20 to Ser (C20S protein), which gives the protein the opportunity either to retain the native structure and use the Ser20 O gamma as a ligand or to rearrange and use Cys24. X-ray crystallography demonstrates that the cluster does not use the Ser20 O gamma as a ligand; rather it rearranges to use Cys24. In the C20S protein the [4Fe-4S] cluster has altered stability and redox properties relative to either C20A or the native protein.