Open AccessExpression, purification, crystallization and preliminary X‐ray analysis of calmodulin in complex with the regulatory domain of the plasma‐membrane Ca 2+ ‐ATPase ACA8
Author(s) -
Tidow Henning,
Hein Kim L.,
Baekgaard Lone,
Palmgren Michael G.,
Nissen Poul
Publication year - 2010
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309110003805
Subject(s) - calmodulin , plasma membrane ca2+ atpase , atpase , microbiology and biotechnology , biology , calcium pump , intracellular , calcium signaling , arabidopsis thaliana , biochemistry , biophysics , enzyme , mutant , gene
Plasma‐membrane Ca 2+ ‐ATPases (PMCAs) are calcium pumps that expel Ca 2+ from eukaryotic cells to maintain overall Ca 2+ homoeostasis and to provide local control of intracellular Ca 2+ signalling. They are of major physiological importance, with different isoforms being essential, for example, for presynaptic and postsynaptic Ca 2+ regulation in neurons, feedback signalling in the heart and sperm motility. In the resting state, PMCAs are autoinhibited by binding of their C‐terminal (in mammals) or N‐terminal (in plants) tail to two major intracellular loops. Activation requires the binding of calcium‐bound calmodulin (Ca 2+ ‐CaM) to this tail and a conformational change that displaces the autoinhibitory tail from the catalytic domain. The complex between calmodulin and the regulatory domain of the plasma‐membrane Ca 2+ ‐ATPase ACA8 from Arabidopsis thaliana has been crystallized. The crystals belonged to space group C 2, with unit‐cell parameters a = 176.8, b = 70.0, c = 69.8 Å, β = 113.2°. A complete data set was collected to 3.0 Å resolution and structure determination is in progress in order to elucidate the mechanism of PMCA activation by calmodulin.