Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
Nat Commun. 2022 Jul 13;13(1):4045. doi: 10.1038/s41467-022-31758-7.
The conversion of light energy to chemical energy by photosynthesis requires the concerted action of large protein complexes in the thylakoid membrane. Recent work has provided fundamental insights into the three-dimensional structure of these complexes, but how they are assembled from hundreds of parts remains poorly understood. Particularly little is known about the biogenesis of the cytochrome bf complex (Cytbf), the redox-coupling complex that interconnects the two photosystems. Here we report the identification of a factor that guides the assembly of Cytbf in thylakoids of chloroplasts. The protein, DE-ETIOLATION-INDUCED PROTEIN 1 (DEIP1), resides in the thylakoid membrane and is essential for photoautotrophic growth. Knock-out mutants show a specific loss of Cytbf, and are defective in complex assembly. We demonstrate that DEIP1 interacts with the two cytochrome subunits of the complex, PetA and PetB, and mediates the assembly of intermediates in Cytbf biogenesis. The identification of DEIP1 provides an entry point into the study of the assembly pathway of a crucial complex in photosynthetic electron transfer.
光合作用将光能转化为化学能需要类囊体膜中大型蛋白质复合物的协同作用。最近的工作为这些复合物的三维结构提供了基本的见解，但它们如何由数百个部分组装仍然知之甚少。关于细胞色素 bf 复合物（Cytbf）的生物发生，即连接两个光系统的氧化还原偶联复合物，了解尤其甚少。在这里，我们报告了一种指导叶绿体类囊体中 Cytbf 组装的因子的鉴定。该蛋白，去黄化诱导蛋白 1（DEIP1），位于类囊体膜中，对于光自养生长是必需的。敲除突变体表现出特定的 Cytbf 缺失，并且在复合物组装中存在缺陷。我们证明 DEIP1 与复合物的两个细胞色素亚基 PetA 和 PetB 相互作用，并介导 Cytbf 生物发生过程中中间体的组装。DEIP1 的鉴定为研究光合作用电子传递中关键复合物的组装途径提供了切入点。
