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Title | Uphill energy transfer mechanism for photosynthesis in an Antarctic alga. |
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Journal, issue, pages | Nat Commun, Vol. 14, Issue 1, Page 730, Year 2023 |
Publish date | Feb 15, 2023 |
Authors | Makiko Kosugi / Masato Kawasaki / Yutaka Shibata / Kojiro Hara / Shinichi Takaichi / Toshio Moriya / Naruhiko Adachi / Yasuhiro Kamei / Yasuhiro Kashino / Sakae Kudoh / Hiroyuki Koike / Toshiya Senda / |
PubMed Abstract | Prasiola crispa, an aerial green alga, forms layered colonies under the severe terrestrial conditions of Antarctica. Since only far-red light is available at a deep layer of the colony, P. crispa has ...Prasiola crispa, an aerial green alga, forms layered colonies under the severe terrestrial conditions of Antarctica. Since only far-red light is available at a deep layer of the colony, P. crispa has evolved a molecular system for photosystem II (PSII) excitation using far-red light with uphill energy transfer. However, the molecular basis underlying this system remains elusive. Here, we purified a light-harvesting chlorophyll (Chl)-binding protein complex from P. crispa (Pc-frLHC) that excites PSII with far-red light and revealed its ring-shaped structure with undecameric 11-fold symmetry at 3.13 Å resolution. The primary structure suggests that Pc-frLHC evolved from LHCI rather than LHCII. The circular arrangement of the Pc-frLHC subunits is unique among eukaryote LHCs and forms unprecedented Chl pentamers at every subunit‒subunit interface near the excitation energy exit sites. The Chl pentamers probably contribute to far-red light absorption. Pc-frLHC's unique Chl arrangement likely promotes PSII excitation with entropy-driven uphill excitation energy transfer. |
External links | Nat Commun / PubMed:36792917 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.13 Å |
Structure data | EMDB-35080, PDB-8hw1: |
Chemicals | ChemComp-CLA: ChemComp-XAT: ChemComp-32N: |
Source |
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Keywords | PHOTOSYNTHESIS / undecameric ring / light-harvesting complex |