title: SOS3 (salt overly sensitive 3) from Arabidopsis thaliana: expression, purification, crystallization and preliminary X-ray analysis.
abstract: The salt-tolerance gene SOS3 (salt overly sensitive 3) of Arabidopsis thaliana encodes a calcium-binding protein that is able to sense the cytosolic calcium signal elicited by salt stress. SOS3 activates the SOS2 protein kinase, which activates various ion transporters. SOS3 was cloned into a plasmid and expressed in Escherichia coli, allowing purification of the protein to homogeneity. Two crystals with different additive contents were grown. Both diffract to 3.2 A resolution and belong to space group I4(1), with unit-cell parameters a = 93.65, c = 80.08 A and a = 91.79, c = 85.78 A, respectively. A promising molecular-replacement solution has been found using neuronal calcium-sensor 1 as the search model. Interestingly, no solution was found using AtCBL2 (A. thaliana calcineurin B-like protein) structure as a search model, although this protein belongs to the same family and displays 50% sequence identity.
authors.affiliation: Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, Serrano 119, E-28006 Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Sánchez-Barrena
authors.forename: M
authors.initials: M
authors.lastname: Martínez-Ripoll
authors.forename: J K
authors.initials: JK
authors.lastname: Zhu
authors.forename: A
authors.initials: A
authors.lastname: Albert
mesh_terms: D017360:Arabidopsis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003460:Crystallization; D018360:Crystallography, X-Ray; D015870:Gene Expression
chemical_list: D029681:Arabidopsis Proteins; C112941:SOS3 protein, Arabidopsis