View source for 2xtz


==Crystal structure of the G alpha protein AtGPA1 from Arabidopsis thaliana==
<StructureSection load='2xtz' size='340' side='right'caption='[[2xtz]], [[Resolution|resolution]] 2.34&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2xtz]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2XTZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2XTZ 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]] 2.34&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=CSS:S-MERCAPTOCYSTEINE'>CSS</scene>, <scene name='pdbligand=GSP:5-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE'>GSP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=2xtz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2xtz OCA], [https://pdbe.org/2xtz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2xtz RCSB], [https://www.ebi.ac.uk/pdbsum/2xtz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2xtz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GPA1_ARATH GPA1_ARATH] Exhibits a fast rate of basal nucleotide exchange. Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. Together with GCR1, may regulate the cell cycle via a signaling cascade that uses phosphatidylinositol-specific phospholipase C (PI-PLC) as an effector and inositol 1,4,5-trisphosphate(IP(3)) as a second messenger. Promotes abscisic acid (ABA) responses in guard cells. But, together with GCR1 and GB1, acts as a negative regulator of ABA during seed germination and early seedling development. Involved in the blue light (BL) signaling. Together with GCR1 and ADT3, required for BL-mediated synthesis of phenylpyruvate and subsequently of phenylalanine (Phe), in etiolated seedlings. Modulates root architecture (e.g. lateral root formation). Negatively regulated by RGS1.<ref>PMID:15155892</ref> <ref>PMID:16415218</ref> <ref>PMID:16581874</ref> <ref>PMID:17322342</ref> <ref>PMID:20862254</ref> <ref>PMID:21304159</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In animals, heterotrimeric guanine nucleotide-binding protein (G protein) signaling is initiated by G protein-coupled receptors (GPCRs), which activate G protein alpha subunits; however, the plant Arabidopsis thaliana lacks canonical GPCRs, and its G protein alpha subunit (AtGPA1) is self-activating. To investigate how AtGPA1 becomes activated, we determined its crystal structure. AtGPA1 is structurally similar to animal G protein alpha subunits, but our crystallographic and biophysical studies revealed that it had distinct properties. Notably, the helical domain of AtGPA1 displayed pronounced intrinsic disorder and a tendency to disengage from the Ras domain of the protein. Domain substitution experiments showed that the helical domain of AtGPA1 was necessary for self-activation and sufficient to confer self-activation to an animal G protein alpha subunit. These findings reveal the structural basis for a mechanism for G protein activation in Arabidopsis that is distinct from the well-established mechanism found in animals.

The crystal structure of a self-activating G protein {alpha} subunit reveals its distinct mechanism of signal initiation.,Jones JC, Duffy JW, Machius M, Temple BR, Dohlman HG, Jones AM Sci Signal. 2011 Feb 8;4(159):ra8. PMID:21304159<ref>PMID:21304159</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 2xtz" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arabidopsis thaliana]]
[[Category: Large Structures]]
[[Category: Dohlman HG]]
[[Category: Duffy JW]]
[[Category: Jones AM]]
[[Category: Jones JC]]
[[Category: Machius M]]
[[Category: Temple BRS]]