8XLP

Structure of inactive Photosystem II associated with CAC antenna from Rhodomonas Salina

Summary for 8XLP

• Entry DOI: 10.2210/pdb8xlp/pdb
• EMDB information: 38455
• Descriptor: Photosystem II protein D1, Photosystem II reaction center protein L, Photosystem II protein M, ... (40 entities in total)
• Functional Keywords: photosystem ii associated with cac antenna from rhodomonas salina, photosynthesis
• Biological source: Rhodomonas salina; More
• Total number of polymer chains: 46
• Total formula weight: 1134951.86

Authors

Si, L.,Li, M. (deposition date: 2023-12-26, release date: 2024-07-31, Last modification date: 2025-06-25)

Primary citation

Si, L.,Zhang, S.,Su, X.,Li, M.
Structural basis for the distinct core-antenna assembly of cryptophyte photosystem II.
Nat Commun, 15:6812-6812, 2024

PubMed Abstract: Photosystem II (PSII) catalyzes the light-driven charge separation and water oxidation reactions of photosynthesis. Eukaryotic PSII core is usually associated with membrane-embedded light-harvesting antennae, which greatly increase the absorbance cross-section of the core. The peripheral antennae in different phototrophs vary considerably in protein composition and arrangement. Photosynthetic cryptophytes possess chlorophyll a/c binding proteins (CACs) that serve as their antennae. How these CACs assemble with the PSII core remains unclear. Here, we report the 2.57-Å resolution structure of cryptophyte PSII-CAC purified from cells at nitrogen-limited stationary growth phase. We show that each monomer of the PSII homodimer contains a core complex, six chlorophyll a/c binding proteins (CACs) and a previously unseen chlorophyll-binding protein (termed CAL-II). Six CACs are arranged as a double-layered arc-shaped non-parallel belt, and two such belts attach to the dimeric core from opposite sides. The CAL-II simultaneously interacts with a number of core subunits and five CACs. The distinct organization of CACs and the presence of CAL-II may play a critical role in stabilizing the dimeric PSII-CAC complex under stress conditions. Our study provides mechanistic insights into the assembly and function of the PSII-CAC complex as well as the possible adaptation of cryptophytes in response to environmental stresses.

PubMed: 39122741
DOI: 10.1038/s41467-024-51206-y

Experimental method

ELECTRON MICROSCOPY (2.57 Å)