Concentration-dependent oligomerization of cross-linked complexes between ferredoxin and ferredoxin-NADP+ reductase
Concentration-dependent oligomerization of cross-linked complexes between ferredoxin and ferredoxin-NADP+ reductase
复制标题
铁氧还蛋白和铁氧还蛋白-NADP还原酶之间交联复合物的浓度依赖性寡聚化
DOI：
10.1016/j.bbrc.2013.04.033
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发表时间：
2013
影响因子：
3.1
通讯作者：
Toshiharu Hase
中科院分区：
文献类型：
--
作者：
Yoko Kimata-Ariga;Hisako Kubota-Kawai;Young-Ho Lee;Norifumi Muraki;Takahisa Ikegami;Genji Kurisu;Toshiharu Hase
铁氧还蛋白-NADP+还原酶（FNR）与铁氧还蛋白（Fd）形成1：1的复合物，催化Fd与NADP+之间的电子转移。在我们之前的研究中，我们制备了一系列的Fd和FNR的位点特异性交联复合物，其显示出不同的电子转移性质。在这里，我们表明，X射线晶体结构的两个不同的Fd-FNR交联复合物形成低聚物通过交换Fd和FNR部分的分子;一个复合物是二聚体，从，和其他是一个连续的多聚体形式。为了验证这些低聚物结构是否仅在晶体中形成，我们研究了这些配合物在溶液中发生低聚的可能性。这些交联复合物的粒径的平均值被证明是增加与蛋白质浓度的上升，在亚毫摩尔级，而解离的野生型Fd：FNR复合物的大小不变，通过动态光散射测量分析。这些复合物在亚毫摩尔浓度下化学交联后，通过SDS-PAGE检测寡聚化产物。两种交联复合物之间的寡聚化的程度和浓度依赖性的配置文件进行了区分。这些结果表明，这些Fd-FNR交联的复合物表现出浓度依赖性的寡聚化，可能是通过在溶液中也交换Fd和FNR部分。这些发现导致了一些天然多结构域蛋白可能在体内呈现类似现象的可能性。
Ferredoxin–NADP+reductase (FNR) forms a 1:1 complex with ferredoxin (Fd), and catalyzes the electron transfer between Fd and NADP+. In our previous study, we prepared a series of site-specifically cross-linked complexes of Fd and FNR, which showed diverse electron transfer properties. Here, we show that X-ray crystal structures of the two different Fd–FNR cross-linked complexes form oligomers by swapping Fd and FNR moieties across the molecules; one complex is a dimer from, and the other is a successive multimeric form. In order to verify whether these oligomeric structures are formed only in crystal, we investigated the possibility of the oligomerization of these complexes in solution. The mean values of the particle size of these cross-linked complexes were shown to increase with the rise of protein concentration at sub-milimolar order, whereas the size of dissociable wild-type Fd:FNR complex was unchanged as analyzed by dynamic light scattering measurement. The oligomerization products were detected by SDS–PAGE after chemical cross-linking of these complexes at the sub-milimolar concentrations. The extent and concentration-dependent profile of the oligomerizaion were differentiated between the two cross-linked complexes. These results show that these Fd–FNR cross-linked complexes exhibit concentration-dependent oligomerization, possibly through swapping of Fd and FNR moieties also in solution. These findings lead to the possibility that some native multi-domain proteins may present similar phenomenon in vivo.