7XZI

Cryo-EM structure of TOC-TIC supercomplex from Chlamydomonas reinhardtii

7XZI の概要

• エントリーDOI: 10.2210/pdb7xzi/pdb
• EMDBエントリー: 33528
• 分子名称: Ctap3, Tic100, Tic56, ... (20 entities in total)
• 機能のキーワード: complex, membrane protein, translocase
• 由来する生物種: Chlamydomonas reinhardtii (Chlamydomonas smithii); 詳細
• タンパク質・核酸の鎖数: 14
• 化学式量合計: 830924.92

構造登録者

Liu, H.,Li, A.J.,Liu, Z.F. (登録日: 2022-06-02, 公開日: 2023-01-11, 最終更新日: 2024-10-30)

主引用文献

Liu, H.,Li, A.,Rochaix, J.D.,Liu, Z.
Architecture of chloroplast TOC-TIC translocon supercomplex.
Nature, 615:349-357, 2023

PubMed Abstract: Chloroplasts rely on the translocon complexes in the outer and inner envelope membranes (the TOC and TIC complexes, respectively) to import thousands of different nuclear-encoded proteins from the cytosol. Although previous studies indicated that the TOC and TIC complexes may assemble into larger supercomplexes, the overall architectures of the TOC-TIC supercomplexes and the mechanism of preprotein translocation are unclear. Here we report the cryo-electron microscopy structure of the TOC-TIC supercomplex from Chlamydomonas reinhardtii. The major subunits of the TOC complex (Toc75, Toc90 and Toc34) and TIC complex (Tic214, Tic20, Tic100 and Tic56), three chloroplast translocon-associated proteins (Ctap3, Ctap4 and Ctap5) and three newly identified small inner-membrane proteins (Simp1-3) have been located in the supercomplex. As the largest protein, Tic214 traverses the inner membrane, the intermembrane space and the outer membrane, connecting the TOC complex with the TIC proteins. An inositol hexaphosphate molecule is located at the Tic214-Toc90 interface and stabilizes their assembly. Four lipid molecules are located within or above an inner-membrane funnel formed by Tic214, Tic20, Simp1 and Ctap5. Multiple potential pathways found in the TOC-TIC supercomplex may support translocation of different substrate preproteins into chloroplasts.

PubMed: 36702157
DOI: 10.1038/s41586-023-05744-y

実験手法

ELECTRON MICROSCOPY (2.77 Å)