View source for 4mkv


==Structure of Pisum sativum Rubisco with ABA==
<StructureSection load='4mkv' size='340' side='right'caption='[[4mkv]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4mkv]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Pisum_sativum Pisum sativum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4MKV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4MKV 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]] 2.15&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=A8S:(2Z,4E)-5-[(1S)-1-HYDROXY-2,6,6-TRIMETHYL-4-OXOCYCLOHEX-2-EN-1-YL]-3-METHYLPENTA-2,4-DIENOIC+ACID'>A8S</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=RUB:RIBULOSE-1,5-DIPHOSPHATE'>RUB</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=4mkv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4mkv OCA], [https://pdbe.org/4mkv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4mkv RCSB], [https://www.ebi.ac.uk/pdbsum/4mkv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4mkv ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RBL_PEA RBL_PEA] RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate in the photorespiration process. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Abscisic acid ((+)-ABA) is a phytohormone involved in the modulation of developmental processes and stress responses in plants. A chemical proteomics approach using an ABA mimetic probe was combined with in vitro assays, isothermal titration calorimetry (ITC), x-ray crystallography and in silico modelling to identify putative (+)-ABA binding-proteins in crude extracts of Arabidopsis thaliana. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) was identified as a putative ABA-binding protein. Radiolabelled-binding assays yielded a Kd of 47 nM for (+)-ABA binding to spinach Rubisco, which was validated by ITC, and found to be similar to reported and experimentally derived values for the native ribulose-1,5-bisphosphate (RuBP) substrate. Functionally, (+)-ABA caused only weak inhibition of Rubisco catalytic activity (Ki of 2.1 mM), but more potent inhibition of Rubisco activation (Ki of ~ 130 muM). Comparative structural analysis of Rubisco in the presence of (+)-ABA with RuBP in the active site revealed only a putative low occupancy (+)-ABA binding site on the surface of the large subunit at a location distal from the active site. However, subtle distortions in electron density in the binding pocket and in silico docking support the possibility of a higher affinity (+)-ABA binding site in the RuBP binding pocket. Overall we conclude that (+)-ABA interacts with Rubisco. While the low occupancy (+)-ABA binding site and weak non-competitive inhibition of catalysis may not be relevant, the high affinity site may allow ABA to act as a negative effector of Rubisco activation.

Identification of Interactions between Abscisic Acid and Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase.,Galka MM, Rajagopalan N, Buhrow LM, Nelson KM, Switala J, Cutler AJ, Palmer DR, Loewen PC, Abrams SR, Loewen MC PLoS One. 2015 Jul 21;10(7):e0133033. doi: 10.1371/journal.pone.0133033., eCollection 2015. PMID:26197050<ref>PMID:26197050</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4mkv" style="background-color:#fffaf0;"></div>

==See Also==
*[[RuBisCO 3D structures|RuBisCO 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Pisum sativum]]
[[Category: Loewen MC]]
[[Category: Loewen PC]]
[[Category: Switala J]]