4dpb

<StructureSection load='4dpb' size='340' side='right' caption='[[4dpb]], [[Resolution|resolution]] 1.00&Aring;' scene=''>

<table><tr><td colspan='2'>[[4dpb]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Populus_nigra Populus nigra]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4DPB OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4DPB FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CU:COPPER+(II)+ION'>CU</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1plc|1plc]], [[4dp0|4dp0]], [[4dp1|4dp1]], [[4dp2|4dp2]], [[4dp4|4dp4]], [[4dp5|4dp5]], [[4dp6|4dp6]], [[4dp7|4dp7]], [[4dp8|4dp8]], [[4dp9|4dp9]], [[4dpa|4dpa]], [[4dpc|4dpc]]</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4dpb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4dpb OCA], [http://pdbe.org/4dpb PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4dpb RCSB], [http://www.ebi.ac.uk/pdbsum/4dpb PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4dpb ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/PLAS1_POPNI PLAS1_POPNI]] Participates in electron transfer between P700 and the cytochrome b6-f complex in photosystem I.

Plastocyanin (PC) from poplar leaves is present in two isoforms, PCa and PCb, which differ in sequence by amino acid replacements at locations remote from the copper center and simultaneously act in the photosynthetic electron-transport chain. We describe ultra-high resolution structures of PCa and high-resolution structures of PCb, both under oxidizing and reducing conditions at pH 4, 6 and 8. The docking on cytochrome f and photosystem I, respectively, has been modeled for both isoforms. PCa and PCb exhibit closely similar overall and active-site structures, except for a difference in the relative orientation of the acidic patches. The isoforms exhibit substantial differences in the dependence of the reduced (Cu(I)) geometry on pH. In PCa, the decrease in pH causes a gradual dissociation of His87 from Cu(I) at low pH, probably adopting a neutral tautomeric state. In PCb, the histidine remains covalently bound to Cu(I) and may adopt a doubly protonated state at low pH. The fact that both isoforms have similar although not identical functions in photosynthetic electron flows suggests that the His87 imidazole does not play a crucial role for the pathway of electron transport from cytochrome f to oxidized PC.

 

== References ==

[[Category: Bartunik, H D]]

[[Category: Bourenkov, G P]]

[[Category: Dimitrov, M I]]

[[Category: Donchev, A A]]

[[Category: Kachalova, G S]]

[[Category: Shosheva, A H]]

[[Category: Transit peptide]]