2eat
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(New page: 200px<br /><applet load="2eat" size="450" color="white" frame="true" align="right" spinBox="true" caption="2eat, resolution 2.90Å" /> '''Crystal structure of...)
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Revision as of 07:52, 21 November 2007
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Crystal structure of the SR CA2+-ATPASE with bound CPA and TG
Overview
Ca(2+)-ATPase of skeletal muscle sarcoplasmic reticulum is an ATP-driven, Ca(2+) pump consisting of three cytoplasmic domains and 10 transmembrane, helices. In the absence of Ca(2+), the three cytoplasmic domains gather to, form a compact headpiece, but the ATPase is unstable without an inhibitor., Here we describe the crystal structures of Ca(2+)-ATPase in the absence of, Ca(2+) stabilized with cyclopiazonic acid alone and in combination with, other inhibitors. Cyclopiazonic acid is located in the transmembrane, region of the protein near the cytoplasmic surface. The binding site, partially overlaps with that of 2,5-di-tert-butyl-1,4-dihydroxybenzene but, is separate from that of thapsigargin. The overall structure is, significantly different from that stabilized with thapsigargin: The, cytoplasmic headpiece is more upright, and the transmembrane helices M1-M4, are rearranged. Cyclopiazonic acid primarily alters the position of the, M1' helix and thereby M2 and M4 and then M5. Because M5 is integrated into, the phosphorylation domain, the whole cytoplasmic headpiece moves. These, structural changes show how an event in the transmembrane domain can be, transmitted to the cytoplasmic domain despite flexible links between them., They also reveal that Ca(2+)-ATPase has considerable plasticity even when, fixed by a transmembrane inhibitor, presumably to accommodate thermal, fluctuations.
About this Structure
2EAT is a Single protein structure of sequence from Oryctolagus cuniculus with TG1 and CZA as ligands. Active as Calcium-transporting ATPase, with EC number 3.6.3.8 Full crystallographic information is available from OCA.
Reference
Interdomain communication in calcium pump as revealed in the crystal structures with transmembrane inhibitors., Takahashi M, Kondou Y, Toyoshima C, Proc Natl Acad Sci U S A. 2007 Apr 3;104(14):5800-5. Epub 2007 Mar 26. PMID:17389383
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