1ej3

CRYSTAL STRUCTURE OF AEQUORIN

spinqualitylabelsall models 1ej3, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ej3 is a 2 chain structure with sequence from Aequorea aequorea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CZH Resources: FirstGlance, OCA, RCSB, PDBsum Function [AEQ2_AEQVI] Ca(2+)-dependent bioluminescence photoprotein. Displays an emission peak at 470 nm (blue light). Trace amounts of calcium ion trigger the intramolecular oxidation of the chromophore, coelenterazine into coelenteramide and CO(2) with the concomitant emission of light. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Aequorin is a calcium-sensitive photoprotein originally obtained from the jellyfish Aequorea aequorea. Because it has a high sensitivity to calcium ions and is biologically harmless, aequorin is widely used as a probe to monitor intracellular levels of free calcium. The aequorin molecule contains four helix-loop-helix 'EF-hand' domains, of which three can bind calcium. The molecule also contains coelenterazine as its chromophoric ligand. When calcium is added, the protein complex decomposes into apoaequorin, coelenteramide and CO2, accompanied by the emission of light. Apoaequorin can be regenerated into active aequorin in the absence of calcium by incubation with coelenterazine, oxygen and a thiol agent. Cloning and expression of the complementary DNA for aequorin were first reported in 1985 (refs 2, 6), and growth of crystals of the recombinant protein has been described; however, techniques have only recently been developed to prepare recombinant aequorin of the highest purity, permitting a full crystallographic study. Here we report the structure of recombinant aequorin determined by X-ray crystallography. Aequorin is found to be a globular molecule containing a hydrophobic core cavity that accommodates the ligand coelenterazine-2-hydroperoxide. The structure shows protein components stabilizing the peroxide and suggests a mechanism by which calcium activation may occur. The crystal structure of the photoprotein aequorin at 2.3 A resolution.,Head JF, Inouye S, Teranishi K, Shimomura O Nature. 2000 May 18;405(6784):372-6. PMID:10830969 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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