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Title | Structure of a monomeric photosystem I core associated with iron-stress-induced-A proteins from Anabaena sp. PCC 7120. |
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Journal, issue, pages | Nat Commun, Vol. 14, Issue 1, Page 920, Year 2023 |
Publish date | Feb 17, 2023 |
Authors | Ryo Nagao / Koji Kato / Tasuku Hamaguchi / Yoshifumi Ueno / Naoki Tsuboshita / Shota Shimizu / Miyu Furutani / Shigeki Ehira / Yoshiki Nakajima / Keisuke Kawakami / Takehiro Suzuki / Naoshi Dohmae / Seiji Akimoto / Koji Yonekura / Jian-Ren Shen / |
PubMed Abstract | Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions. The cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, their binding property ...Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions. The cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, their binding property and functional roles in PSI are still missing. We analyzed a cryo-electron microscopy structure of a PSI-IsiA supercomplex isolated from Anabaena grown under an iron-deficient condition. The PSI-IsiA structure contains six IsiA subunits associated with the PsaA side of a PSI core monomer. Three of the six IsiA subunits were identified as IsiA1 and IsiA2. The PSI-IsiA structure lacks a PsaL subunit; instead, a C-terminal domain of IsiA2 occupies the position of PsaL, which inhibits the oligomerization of PSI, leading to the formation of a PSI monomer. Furthermore, excitation-energy transfer from IsiAs to PSI appeared with a time constant of 55 ps. These findings provide insights into both the molecular assembly of the Anabaena IsiA family and the functional roles of IsiAs. |
External links | Nat Commun / PubMed:36805598 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.62 Å |
Structure data | EMDB-33593, PDB-7y3f: |
Chemicals | ChemComp-CL0: ChemComp-CLA: ChemComp-PQN: ChemComp-SF4: ChemComp-BCR: ChemComp-LHG: ChemComp-LMT: ChemComp-LMG: ChemComp-HOH: |
Source |
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Keywords | PHOTOSYNTHESIS / Photosystem I / ELECTRON TRANSPORT / isiA |