7o1v: Difference between revisions
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The | ==Structure of a Minimal Photosystem I== | ||
<StructureSection load='7o1v' size='340' side='right'caption='[[7o1v]], [[Resolution|resolution]] 4.31Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[7o1v]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Synechocystis_sp._PCC_6803_substr._Kazusa Synechocystis sp. PCC 6803 substr. Kazusa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7O1V OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7O1V FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 4.31Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BCR:BETA-CAROTENE'>BCR</scene>, <scene name='pdbligand=CLA:CHLOROPHYLL+A'>CLA</scene>, <scene name='pdbligand=ECH:BETA,BETA-CAROTEN-4-ONE'>ECH</scene>, <scene name='pdbligand=LHG:1,2-DIPALMITOYL-PHOSPHATIDYL-GLYCEROLE'>LHG</scene>, <scene name='pdbligand=LMG:1,2-DISTEAROYL-MONOGALACTOSYL-DIGLYCERIDE'>LMG</scene>, <scene name='pdbligand=PQN:PHYLLOQUINONE'>PQN</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene>, <scene name='pdbligand=SQD:1,2-DI-O-ACYL-3-O-[6-DEOXY-6-SULFO-ALPHA-D-GLUCOPYRANOSYL]-SN-GLYCEROL'>SQD</scene></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7o1v FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7o1v OCA], [https://pdbe.org/7o1v PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7o1v RCSB], [https://www.ebi.ac.uk/pdbsum/7o1v PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7o1v ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/PSAB_SYNY3 PSAB_SYNY3] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Photosystem I (PSI), found in all oxygenic photosynthetic organisms, uses solar energy to drive electron transport with nearly 100% quantum efficiency, thanks to fast energy transfer among antenna chlorophylls and charge separation in the reaction center. There is no complete consensus regarding the kinetics of the elementary steps involved in the overall trapping, especially the rate of primary charge separation. In this work, we employed two-dimensional coherent electronic spectroscopy to follow the dynamics of energy and electron transfer in a monomeric PSI complex from Synechocystis PCC 6803, containing only subunits A-E, K, and M, at 77 K. We also determined the structure of the complex to 4.3 A resolution by cryoelectron microscopy with refinements to 2.5 A. We applied structure-based modeling using a combined Redfield-Forster theory to compute the excitation dynamics. The absorptive 2D electronic spectra revealed fast excitonic/vibronic relaxation on time scales of 50-100 fs from the high-energy side of the absorption spectrum. Antenna excitations were funneled within 1 ps to a small pool of chlorophylls absorbing around 687 nm, thereafter decaying with 4-20 ps lifetimes, independently of excitation wavelength. Redfield-Forster energy transfer computations showed that the kinetics is limited by transfer from these red-shifted pigments. The rate of primary charge separation, upon direct excitation of the reaction center, was determined to be 1.2-1.5 ps(-1). This result implies activationless electron transfer in PSI. | |||
Two-Dimensional Electronic Spectroscopy of a Minimal Photosystem I Complex Reveals the Rate of Primary Charge Separation.,Akhtar P, Caspy I, Nowakowski PJ, Malavath T, Nelson N, Tan HS, Lambrev PH J Am Chem Soc. 2021 Sep 15;143(36):14601-14612. doi: 10.1021/jacs.1c05010. Epub , 2021 Sep 2. PMID:34472838<ref>PMID:34472838</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
<div class="pdbe-citations 7o1v" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Photosystem I 3D structures|Photosystem I 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Large Structures]] | |||
[[Category: Synechocystis sp. PCC 6803 substr. Kazusa]] | |||
[[Category: Caspy I]] | |||
[[Category: Lambrev P]] | |||
[[Category: Nelson N]] | |||
Latest revision as of 11:59, 14 July 2024
Structure of a Minimal Photosystem IStructure of a Minimal Photosystem I
Structural highlights
FunctionPublication Abstract from PubMedPhotosystem I (PSI), found in all oxygenic photosynthetic organisms, uses solar energy to drive electron transport with nearly 100% quantum efficiency, thanks to fast energy transfer among antenna chlorophylls and charge separation in the reaction center. There is no complete consensus regarding the kinetics of the elementary steps involved in the overall trapping, especially the rate of primary charge separation. In this work, we employed two-dimensional coherent electronic spectroscopy to follow the dynamics of energy and electron transfer in a monomeric PSI complex from Synechocystis PCC 6803, containing only subunits A-E, K, and M, at 77 K. We also determined the structure of the complex to 4.3 A resolution by cryoelectron microscopy with refinements to 2.5 A. We applied structure-based modeling using a combined Redfield-Forster theory to compute the excitation dynamics. The absorptive 2D electronic spectra revealed fast excitonic/vibronic relaxation on time scales of 50-100 fs from the high-energy side of the absorption spectrum. Antenna excitations were funneled within 1 ps to a small pool of chlorophylls absorbing around 687 nm, thereafter decaying with 4-20 ps lifetimes, independently of excitation wavelength. Redfield-Forster energy transfer computations showed that the kinetics is limited by transfer from these red-shifted pigments. The rate of primary charge separation, upon direct excitation of the reaction center, was determined to be 1.2-1.5 ps(-1). This result implies activationless electron transfer in PSI. Two-Dimensional Electronic Spectroscopy of a Minimal Photosystem I Complex Reveals the Rate of Primary Charge Separation.,Akhtar P, Caspy I, Nowakowski PJ, Malavath T, Nelson N, Tan HS, Lambrev PH J Am Chem Soc. 2021 Sep 15;143(36):14601-14612. doi: 10.1021/jacs.1c05010. Epub , 2021 Sep 2. PMID:34472838[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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