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PDBsum entry 1qzv

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Photosynthesis PDB id
1qzv
Jmol
Contents
Protein chains
726 a.a.*
80 a.a.*
154 a.a.*
64 a.a.*
154 a.a.*
74 a.a.*
52 a.a.*
30 a.a.*
41 a.a.*
42 a.a.*
135 a.a.*
109 a.a.*
(+ 0 more) 115 a.a.*
Ligands
CLA ×334
PQN ×4
SF4 ×6
* C-alpha coords only

References listed in PDB file
Key reference
Title Crystal structure of plant photosystem I.
Authors A.Ben-Shem, F.Frolow, N.Nelson.
Ref. Nature, 2003, 426, 630-635. [DOI no: 10.1038/nature02200]
PubMed id 14668855
Abstract
Oxygenic photosynthesis is the principal producer of both oxygen and organic matter on Earth. The conversion of sunlight into chemical energy is driven by two multisubunit membrane protein complexes named photosystem I and II. We determined the crystal structure of the complete photosystem I (PSI) from a higher plant (Pisum sativum var. alaska) to 4.4 A resolution. Its intricate structure shows 12 core subunits, 4 different light-harvesting membrane proteins (LHCI) assembled in a half-moon shape on one side of the core, 45 transmembrane helices, 167 chlorophylls, 3 Fe-S clusters and 2 phylloquinones. About 20 chlorophylls are positioned in strategic locations in the cleft between LHCI and the core. This structure provides a framework for exploration not only of energy and electron transfer but also of the evolutionary forces that shaped the photosynthetic apparatus of terrestrial plants after the divergence of chloroplasts from marine cyanobacteria one billion years ago.
Figure 4.
Figure 4: The structural model of Lhca monomers compared to LHCII. a, The experimental electron density map covering the C backbone of Lhca4. b, Experimental electron density map covering the chlorophylls of Lhca4. Chlorophylls in blue have parallels in LHCII whereas the additional linker chlorophylls (see text) are in red. c, Superposition of Lhca2 (green) and LHCII (magenta) backbones. d, Superposition of the chlorophylls of Lhca2 (blue and red) and LHCII (yellow). Note that this Lhca contains only two linker chlorophylls.
Figure 5.
Figure 5: Electron transfer chain and plastocyanin binding. Residues 18 -47 of plant PsaF, which include the 18 residues exclusive to eukaryotes and that form a helix -loop -helix domain, are coloured red. A cluster of four negatively charged residues (red) on the surface of plastocyanin (green) interacts with three lysines (blue) from the N terminus of PsaF, two of which are from the extra 18 residues. The two tryptophan residues (indicated by an arrow) crucial for the electron transfer from the reduced copper to the oxidized P[700], and that contribute to the hydrophobic interaction with plastocyanin, are shown as spherical atoms (cyan and magenta). The histidine residue that coordinates the copper atom in plastocyanin is in blue.
The above figures are reprinted by permission from Macmillan Publishers Ltd: Nature (2003, 426, 630-635) copyright 2003.
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