1iwo
From Proteopedia
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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 with TG1 as ligand. The following page contains interesting information on the relation of 1IWO with [The Calcium Pump]. Active as Calcium-transporting ATPase, with EC number 3.6.3.8 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 Nov 18 09:02:05 2007
