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Full-Text Articles in Life Sciences
Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li
Doctoral Dissertations
Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this tetrameric …
Electron Transport To Photosystem I By Soluble Carriers: Evolution Of The Interacting Pair, Khoa Dang Nguyen
Electron Transport To Photosystem I By Soluble Carriers: Evolution Of The Interacting Pair, Khoa Dang Nguyen
Doctoral Dissertations
Oxygenic photosynthesis is driven via sequential action of Photosystem II (PSII) and (PSI) reaction centers via the Z-‐scheme. Both of these pigment– membrane protein complexes are found in cyanobacteria, algae, and plants. PSI, unlike PSII, is remarkably stable and does not undergo limiting photo-‐damage. This stability, as well as other fundamental structural differences, makes PSI the most attractive reaction centers for applied photosynthetic applications. These applied applications exploit the efficient light harvesting and high quantum yield of PSI where the isolated PSI particles are redeployed providing electrons directly as a photocurrent or, via a coupled catalyst to yield H2. Here, …