1iwo
From Proteopedia
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| , resolution 3.10Å | |||||||
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| Ligands: | |||||||
| Activity: | Calcium-transporting ATPase, with EC number 3.6.3.8 | ||||||
| Related: | 1EUL
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of the SR Ca2+-ATPase in the absence of Ca2+
Overview
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.
About this Structure
1IWO is a Single protein structure of sequence from Oryctolagus cuniculus. The following page contains interesting information on the relation of 1IWO with [The Calcium Pump]. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Sun Mar 30 21:25:42 2008
