Nature Plants, 24 June, 2025, DOI：https://doi.org/10.1038/s41477-025-02036-3

Roles of multiple TEF30-associated intermediate complexes in the repair and reassembly of photosystem II in Chlamydomonas reinhardtii

Yidi Wang, Chenxi Wang, Anjie Li & Zhenfeng Liu

Abstract

During oxygenic photosynthesis, photosystem II (PSII) uses light energy for oxidizing water and reducing plastoquinone. It is susceptible to photodamage, and the damaged PSII is repaired through a sophisticated biological process assisted by numerous auxiliary proteins. Here we report the cryogenic electron microscopy structures of four PSII-repair complexes from Chlamydomonas reinhardtii associated with the Thylakoid Enriched Fraction 30 (TEF30, an orthologue of plant MET1) protein—namely, a TEF30–PSII core monomer (TEF30-C), two types of TEF30–PSII core dimers (types I and II, TEF30₂-C₂-I and TEF30₂-C₂-II) and a TEF30-C₂S-type PSII–LHCII supercomplex (TEF30-C₂S; S, strongly associated light-harvesting complex II trimer). TEF30 mediates the assembly of CP43 with the RC47 module by clamping on the stromal surfaces and prevents the premature association of peripheral antennae with PSII-C. In the transition from TEF30₂-C₂-I to TEF30₂-C₂-II, TEF30-C₂S and mature C₂S₂, one PSII core slides along the dimerization interface against the adjacent one by 22–35 Å, generating a zigzagged surface for accommodating the peripheral antennae. These results suggest that the PSII repair process undergoes multiple TEF30-mediated intermediate states to form intact PSII–LHCII supercomplexes.

Article link：https://www.nature.com/articles/s41477-025-02036-3