Structural Basis for Ca2+ Regulation in the Na+/Ca2+ Exchanger.
From: Department of Biophysical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands. hilge@nmr.ru.nl
Annals of the New York Academy of Sciences
- Publish Date: Mar 2007
- ISSN: 0077-8923
- Volume: 1099
- Issue:
- Pages: 7-15
- Medium: Print
- Language: English
- Citation (JAMA): Hilge Mark, Aelen Jan, Perrakis Anastassis, et al. Structural Basis for Ca2+ Regulation in the Na+/Ca2+ Exchanger.. Ann. N. Y. Acad. Sci. Mar 2007;1099:7-15
Abstract
Binding of Na+ and Ca2+ ions to the large cytosolic loop of the Na+/Ca2+ exchanger (NCX) regulates its ion transport across the plasma membrane. 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 constitute a novel Ca2+-binding motif and are very similar in the Ca2+-bound state. Strikingly, in the absence of Ca2+ the upper half of CBD1 unfolds while CBD2 maintains its structural integrity. Together with a sevenfold 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.
Mesh Headings (Keywords): Amino Acid Sequence, Animals, Binding Sites, Calcium, Dogs, Models, Molecular, Molecular Sequence Data, Protein Conformation, Sequence Homology, Amino Acid, Sodium-Calcium Exchanger
Check for Full Text / PubMed Unique Identifier (PMID): 17347334
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.