2fwu
From Proteopedia
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| Ligands: | |||||||
| Gene: | NCX1 (Canis lupus familiaris) | ||||||
| Related: | 2FWS
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Second Ca2+ binding domain of the Na,Ca-exchanger (NCX1)
Overview
The plasma membrane Na+/Ca2+ exchanger (NCX) is almost certainly the major Ca2+ extrusion mechanism in cardiac myocytes. Binding of Na+ and Ca2+ ions to its large cytosolic loop regulates ion transport of the exchanger. We determined the solution structures of two Ca2+ binding domains (CBD1 and CBD2) that, together with an alpha-catenin-like domain (CLD), form the regulatory exchanger loop. CBD1 and CBD2 are very similar in the Ca2+ bound state and describe the Calx-beta motif. Strikingly, in the absence of Ca2+, the upper half of CBD1 unfolds while CBD2 maintains its structural integrity. Together with a 7-fold higher affinity for Ca2+, this suggests that CBD1 is the primary Ca2+ sensor. Specific point mutations in either domain largely allow the interchange of their functionality and uncover the mechanism underlying Ca2+ sensing in NCX.
About this Structure
2FWU is a Single protein structure of sequence from Canis lupus familiaris. Full crystallographic information is available from OCA.
Reference
Ca2+ regulation in the Na+/Ca2+ exchanger involves two markedly different Ca2+ sensors., Hilge M, Aelen J, Vuister GW, Mol Cell. 2006 Apr 7;22(1):15-25. PMID:16600866
Page seeded by OCA on Mon Mar 31 03:08:45 2008
