National Natural Science Foundation of China (NSFC)
中国
引用
ジャーナル: Mol Plant / 年: 2024 タイトル: Architecture of the ATP-driven motor for protein import into chloroplasts. 著者: Ning Wang / Jiale Xing / Xiaodong Su / Junting Pan / Hui Chen / Lifang Shi / Long Si / Wenqiang Yang / Mei Li / 要旨: Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC-TIC translocon that spans the chloroplast envelope membranes. A motor complex pulls the translocated proteins ...Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC-TIC translocon that spans the chloroplast envelope membranes. A motor complex pulls the translocated proteins out of the TOC-TIC complex into the chloroplast stroma by hydrolyzing ATP. The Orf2971-FtsHi complex has been suggested to serve as the ATP-hydrolyzing motor in Chlamydomonas reinhardtii, but little is known about its architecture and assembly. Here, we report the 3.2-Å resolution structure of the Chlamydomonas Orf2971-FtsHi complex. The 20-subunit complex spans the chloroplast inner envelope, with two bulky modules protruding into the intermembrane space and stromal matrix. Six subunits form a hetero-hexamer that potentially provides the pulling force through ATP hydrolysis. The remaining subunits, including potential enzymes/chaperones, likely facilitate the complex assembly and regulate its proper function. Taken together, our results provide the structural foundation for a mechanistic understanding of chloroplast protein translocation.