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| Title | Structural basis for the distinct core-antenna assembly of cryptophyte photosystem II. |
|---|---|
| Journal, issue, pages | Nat Commun, Vol. 15, Issue 1, Page 6812, Year 2024 |
| Publish date | Aug 9, 2024 |
Authors | Long Si / Shumeng Zhang / Xiaodong Su / Mei Li / ![]() |
| 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 ...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. |
External links | Nat Commun / PubMed:39122741 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.57 - 2.9 Å |
| Structure data | EMDB-38455, PDB-8xlp: ![]() EMDB-38912: Overall map of PSII-CAC ![]() EMDB-38913: Focus refinement map of PSII-CAC |
| Chemicals | ![]() ChemComp-FE2: ![]() ChemComp-CLA: ![]() ChemComp-PHO: ![]()
ChemComp-WVN: ![]() ChemComp-SQD: ![]() ChemComp-PL9: ![]() ChemComp-BCT: ![]() ChemComp-LHG: ![]() ChemComp-CL: ![]() ChemComp-MN: ![]() ChemComp-LMG: ![]() ChemComp-DGD: ![]() ChemComp-HEM: ![]() ChemComp-KC2: ![]() ChemComp-II0: ![]() ChemComp-IHT: ![]() ChemComp-HOH: |
| Source |
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Keywords | PHOTOSYNTHESIS / Photosystem II associated with CAC antenna from Rhodomonas Salina |
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rhodomonas salina (eukaryote)
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