View source for 1a0r


==HETEROTRIMERIC COMPLEX OF PHOSDUCIN/TRANSDUCIN BETA-GAMMA==
<StructureSection load='1a0r' size='340' side='right'caption='[[1a0r]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1a0r]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A0R OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1A0R 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]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=FAR:FARNESYL'>FAR</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=1a0r FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a0r OCA], [https://pdbe.org/1a0r PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1a0r RCSB], [https://www.ebi.ac.uk/pdbsum/1a0r PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1a0r ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GBB1_BOVIN GBB1_BOVIN] Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction.
== 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/a0/1a0r_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=1a0r ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: Phosducin binds tightly to the beta gamma subunits (Gt beta gamma) of the heterotrimeric G protein transducin, preventing Gt beta gamma reassociation with Gt alpha-GDP and thereby inhibiting the G-protein cycle. Phosducin-like proteins appear to be widely distributed and may play important roles in regulating many heterotrimeric G-protein signaling pathways. RESULTS: The 2.8 A crystal structure of a complex of bovine retinal phosducin with Gt beta gamma shows how the two domains of phosducin cover one side and the top of the seven-bladed beta propeller of Gt beta gamma. The binding of phosducin induces a distinct structural change in the beta propeller of Gt beta gamma, such that a small cavity opens up between blades 6 and 7. Electron density in this cavity has been assigned to the farnesyl moiety of the gamma subunit. CONCLUSIONS: beta gamma subunits of heterotrimeric G proteins can exist in two distinct conformations. In the R (relaxed) state, corresponding to the structure of the free beta gamma or the structure of beta gamma in the alpha beta gamma heterotrimer, the hydrophobic farnesyl moiety of the gamma subunit is exposed, thereby mediating membrane association. In the T (tense) state, as observed in the phosducin-Gt beta gamma structure, the farnesyl moiety of the gamma subunit is effectively buried in the cavity formed between blades 6 and 7 of the beta subunit. Binding of phosducin to Gt beta gamma induces the formation of this cavity, resulting in a switch from the R to the T conformation. This sequesters beta gamma from the membrane to the cytosol and turns off the signal-transduction cascade. Regulation of this membrane association/dissociation switch of Gt beta gamma by phosducin may be a general mechanism for attenuation of G protein coupled signal transduction cascades.

Phosducin induces a structural change in transducin beta gamma.,Loew A, Ho YK, Blundell T, Bax B Structure. 1998 Aug 15;6(8):1007-19. PMID:9739091<ref>PMID:9739091</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Transducin 3D structures|Transducin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Bax B]]
[[Category: Blundell TL]]
[[Category: Ho Y-K]]
[[Category: Loew A]]