View source for 3aeq


==Structure of the light-independent protochlorophyllide reductase catalyzing a key reduction for greening in the dark==
<StructureSection load='3aeq' size='340' side='right'caption='[[3aeq]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3aeq]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Rhodobacter_capsulatus Rhodobacter capsulatus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3AEQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3AEQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.9&#8491;</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=3aeq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3aeq OCA], [https://pdbe.org/3aeq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3aeq RCSB], [https://www.ebi.ac.uk/pdbsum/3aeq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3aeq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BCHN_RHOCB BCHN_RHOCB] Component of the dark-operative protochlorophyllide reductase (DPOR) that uses Mg-ATP and reduced ferredoxin to reduce ring D of protochlorophyllide (Pchlide) to form chlorophyllide a (Chlide). This reaction is light-independent. The NB-protein (BchN-BchB) is the catalytic component of the complex.[HAMAP-Rule:MF_00352]<ref>PMID:18358835</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ae/3aeq_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3aeq ConSurf].
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== Publication Abstract from PubMed ==
Photosynthetic organisms adopt two different strategies for the reduction of the C17 = C18 double bond of protochlorophyllide (Pchlide) to form chlorophyllide a, the direct precursor of chlorophyll a (refs 1-4). The first involves the activity of the light-dependent Pchlide oxidoreductase, and the second involves the light-independent (dark-operative) Pchlide oxidoreductase (DPOR). DPOR is a nitrogenase-like enzyme consisting of two components, L-protein (a BchL dimer) and NB-protein (a BchN-BchB heterotetramer), which are structurally related to nitrogenase Fe protein and MoFe protein, respectively. Here we report the crystal structure of the NB-protein of DPOR from Rhodobacter capsulatus at a resolution of 2.3A. As expected, the overall structure is similar to that of nitrogenase MoFe protein: each catalytic BchN-BchB unit contains one Pchlide and one iron-sulphur cluster (NB-cluster) coordinated uniquely by one aspartate and three cysteines. Unique aspartate ligation is not necessarily needed for the cluster assembly but is essential for the catalytic activity. Specific Pchlide-binding accompanies the partial unwinding of an alpha-helix that belongs to the next catalytic BchN-BchB unit. We propose a unique trans-specific reduction mechanism in which the distorted C17-propionate of Pchlide and an aspartate from BchB serve as proton donors for C18 and C17 of Pchlide, respectively. Intriguingly, the spatial arrangement of the NB-cluster and Pchlide is almost identical to that of the P-cluster and FeMo-cofactor in nitrogenase MoFe-protein, illustrating that a common architecture exists to reduce chemically stable multibonds of porphyrin and dinitrogen.

X-ray crystal structure of the light-independent protochlorophyllide reductase.,Muraki N, Nomata J, Ebata K, Mizoguchi T, Shiba T, Tamiaki H, Kurisu G, Fujita Y Nature. 2010 May 6;465(7294):110-4. PMID:20400946<ref>PMID:20400946</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rhodobacter capsulatus]]
[[Category: Fujita Y]]
[[Category: Kurisu G]]
[[Category: Muraki N]]
[[Category: Nomata J]]
[[Category: Shiba T]]