The universally conserved HCF101 protein is involved in assembly of [4Fe-4S]-cluster-containing complexes in Arabidopsis thaliana chloroplasts
The universally conserved HCF101 protein is involved in assembly of [4Fe-4S]-cluster-containing complexes in Arabidopsis thaliana chloroplasts
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DOI：
10.1046/j.1365-313x.2003.01952.x
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发表时间：
2004-01-01
期刊：
影响因子：
7.2
通讯作者：
Meurer, J
中科院分区：
文献类型：
--
作者：
Lezhneva, L;Amann, K;Meurer, J
幼苗致死核拟南芥hcf101(高叶绿素荧光)突变体在光合作用过程中受到损害，并与野生型hcf101互补。光系统I(PSI)活性被取消，PSI核心复合体不能在hcf101中积累，而其他类囊体膜蛋白的水平不受影响。Northern和体内标记分析以及对多聚体负载的研究表明，属于PSI的PSI转录水平和蛋白质的翻译速率在hCF101中是正常的。在hCF101中，77K下PSI特异的荧光从735 nm移动到728 nm，这表明激子不能有效地转移到PSI反应中心，从而PSI天线几乎不受影响。突变植株不仅不能积累含有三个[4Fe-4S]簇(FSCs)的成熟PSI，而且基质中含有FSC的可溶性铁氧还蛋白-硫氧还蛋白还原酶(FTR)水平降低。抑制FTR成熟不是由于缺乏PSI而产生的次要效应，因为同样缺乏PSI的突变体hcf145在正常水平积累FTR。在hcf101植物中，分别含有[2Fe-2S]簇的可溶性蛋白和膜蛋白铁氧还蛋白和PETC的水平没有变化。这些数据表明，HCF101在FSC的生物发生中具有特定的作用。HCF101定位于质体，属于一个古老的、普遍保守的P-loop ATPase家族，以前被命名为‘MRP’(metG相关蛋白)家族。HCF101的功能提示这个家族有一个新的名称，FSC。
The seedling-lethal nuclear Arabidopsis hcf101 (high chlorophyll fluorescence) mutant is impaired in photosynthesis and complemented by the wild-type HCF101 cDNA. Photosystem I (PSI) activity is abolished, and PSI core complexes fail to accumulate in hcf101, whereas levels of other thylakoid membrane proteins are unaffected. Northern and in vivo labelling analyses as well as studies on polysome loading show that PSI transcript levels and translation rates of proteins, which belong to PSI, are normal in hcf101. PSI-specific fluorescence at 77 K is shifted from 735 to 728 nm in hcf101, indicating that exitons cannot efficiently be transferred to the PSI reaction centre, whereby the PSI antenna is almost unaffected. Mutant plants not only fail to accumulate mature PSI, which contains three [4Fe-4S] clusters (FSCs), but also are characterized by reduced levels of the soluble FSC-containing complex ferredoxin-thioredoxin reductase (FTR) in the stroma. Inhibited FTR maturation is not a secondary effect stemming from lack of PSI because the mutant hcf145, which also lacks PSI, accumulates FTR at normal levels. Levels of the [2Fe-2S] cluster-containing soluble and membrane proteins, ferredoxin and PetC, respectively, were unchanged in hcf101 plants. These data suggest a specific role of HCF101 in FSC biogenesis. HCF101 is plastid localized and belongs to an ancient and universally conserved family of P-loop ATPases previously designated as the 'MRP' (metG related protein) family. The function identified for HCF101 suggests a new designation, FSC, for this family.