2dpk | pdb_00002dpk
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The Crystal Structure of the Primary Ca2+ Sensor of the Na+/Ca2+ Exchanger
Overview
The Na+/Ca2+ exchanger is a plasma membrane protein that regulates intracellular Ca2+ levels in cardiac myocytes. Transport activity is governed by Ca2+, and the primary Ca2+ sensor (CBD1) is located in a large cytoplasmic loop connecting two transmembrane helices. The binding of Ca2+ to the CBD1 sensory domain results in conformational changes that stimulate the exchanger to extrude Ca2+. Here, we present a crystal structure of CBD1 at 2.5A resolution, which reveals a novel Ca2+ binding site consisting of four Ca2+ ions arranged in a tight planar cluster. This intricate coordination pattern for a Ca2+ binding cluster is indicative of a highly sensitive Ca2+ sensor and may represent a general platform for Ca2+ sensing.
About this Structure
2DPK is a Single protein structure of sequence from Canis lupus familiaris with CA, GAI and EPE as ligands. Full crystallographic information is available from OCA.
Reference
The crystal structure of the primary Ca2+ sensor of the Na+/Ca2+ exchanger reveals a novel Ca2+ binding motif., Nicoll DA, Sawaya MR, Kwon S, Cascio D, Philipson KD, Abramson J, J Biol Chem. 2006 Aug 4;281(31):21577-81. Epub 2006 Jun 14. PMID:16774926
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