8Z9Y

Cryo-EM Structure of the Arabidopsis thaliana TIC Complex

Summary for 8Z9Y

• Entry DOI: 10.2210/pdb8z9y/pdb
• EMDB information: 39872
• Descriptor: Protein TIC 214, Protein TIC 20-I, chloroplastic, Actin T1-like protein, ... (6 entities in total)
• Functional Keywords: complex, translocase, channel, membrane protein.
• Biological source: Arabidopsis thaliana (thale cress); More
• Total number of polymer chains: 6
• Total formula weight: 449933.95

Authors

Wu, J.,Yan, Z.,Jin, Z.,Xu, Q. (deposition date: 2024-04-23, release date: 2024-11-27, Last modification date: 2025-07-23)

Primary citation

Liang, K.,Jin, Z.,Zhan, X.,Li, Y.,Xu, Q.,Xie, Y.,Yang, Y.,Wang, S.,Wu, J.,Yan, Z.
Structural insights into the chloroplast protein import in land plants.
Cell, 187:5651-5664.e18, 2024

PubMed Abstract: Chloroplast proteins are imported via the translocon at the outer chloroplast membrane (TOC)-translocon at the inner chloroplast membrane (TIC) supercomplex, driven by an ATPase motor. The Ycf2-FtsHi complex has been identified as the chloroplast import motor. However, its assembly and cooperation with the TIC complex during preprotein translocation remain unclear. Here, we present the structures of the Ycf2-FtsHi and TIC complexes from Arabidopsis and an ultracomplex formed between them from Pisum. The Ycf2-FtsHi structure reveals a heterohexameric AAA+ ATPase motor module with characteristic features. Four previously uncharacterized components of Ycf2-FtsHi were identified, which aid in complex assembly and anchoring of the motor module at a tilted angle relative to the membrane. When considering the structures of the TIC complex and the TIC-Ycf2-FtsHi ultracomplex together, it becomes evident that the tilted motor module of Ycf2-FtsHi enables its close contact with the TIC complex, thereby facilitating efficient preprotein translocation. Our study provides valuable structural insights into the chloroplast protein import process in land plants.

PubMed: 39197452
DOI: 10.1016/j.cell.2024.08.003

Experimental method

ELECTRON MICROSCOPY (2.5 Å)