View source for 1iwo


==Crystal structure of the SR Ca2+-ATPase in the absence of Ca2+==
<StructureSection load='1iwo' size='340' side='right'caption='[[1iwo]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1iwo]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. The March 2004 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''The Calcium Pump''  by David S. Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2004_3 10.2210/rcsb_pdb/mom_2004_3]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IWO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IWO 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]] 3.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=TG1:(3S,3aR,4S,6S,6aR,7S,8S,9bS)-6-(acetyloxy)-4-(butanoyloxy)-3,3a-dihydroxy-3,6,9-trimethyl-8-{[(2Z)-2-methylbut-2-enoyl]oxy}-2-oxo-2,3,3a,4,5,6,6a,7,8,9b-decahydroazuleno[4,5-b]furan-7-yl+octanoate'>TG1</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=1iwo FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iwo OCA], [https://pdbe.org/1iwo PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1iwo RCSB], [https://www.ebi.ac.uk/pdbsum/1iwo PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1iwo ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AT2A1_RABIT AT2A1_RABIT] This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen. Contributes to calcium sequestration involved in muscular excitation/contraction (By similarity).
== 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/iw/1iwo_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=1iwo ConSurf].
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== Publication Abstract from PubMed ==
In skeletal muscle, calcium ions are transported (pumped) against a concentration gradient from the cytoplasm into the sarcoplasmic reticulum, an intracellular organelle. This causes muscle cells to relax after cytosolic calcium increases during excitation. The Ca(2+) ATPase that carries out this pumping is a representative P-type ion-transporting ATPase. Here we describe the structure of this ion pump at 3.1 A resolution in a Ca(2+)-free (E2) state, and compare it with that determined previously for the Ca(2+)-bound (E1Ca(2+)) state. The structure of the enzyme stabilized by thapsigargin, a potent inhibitor, shows large conformation differences from that in E1Ca(2+). Three cytoplasmic domains gather to form a single headpiece, and six of the ten transmembrane helices exhibit large-scale rearrangements. These rearrangements ensure the release of calcium ions into the lumen of sarcoplasmic reticulum and, on the cytoplasmic side, create a pathway for entry of new calcium ions.

Structural changes in the calcium pump accompanying the dissociation of calcium.,Toyoshima C, Nomura H Nature. 2002 Aug 8;418(6898):605-11. PMID:12167852<ref>PMID:12167852</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1iwo" style="background-color:#fffaf0;"></div>

==See Also==
*[[ATPase 3D structures|ATPase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Oryctolagus cuniculus]]
[[Category: RCSB PDB Molecule of the Month]]
[[Category: The Calcium Pump]]
[[Category: Nomura H]]
[[Category: Toyoshima C]]