EMD-39202

Single-particle
3.3 Å
EMD-39202 Deposition: 22/02/2024
Map released: 04/12/2024
Last modified: 04/12/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
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EMD-39202

The middle region of Orf2971-FtsHi motor complex

EMD-39202

Single-particle
3.3 Å
EMD-39202 Deposition: 22/02/2024
Map released: 04/12/2024
Last modified: 04/12/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Chlamydomonas reinhardtii
Sample: The middle region of Orf2971-FtsHi motor complex

Deposition Authors: Wang N, Li M
Architecture of the ATP-driven motor for protein import into chloroplasts.
Wang N, Xing J, Su X, Pan J, Chen H, Shi L, Si L, Yang W, Li M
(2024) Mol Plant , 17 , 1702 - 1718
PUBMED: 39327731
DOI: doi:10.1016/j.molp.2024.09.010
ISSN: 1752-9867
Abstract:
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.