title: Crystallization and preliminary X-ray diffraction analysis of calexcitin from Loligo pealei: a neuronal protein implicated in learning and memory.
abstract: The neuronal protein calexcitin from the long-finned squid Loligo pealei has been expressed in Escherichia coli and purified to homogeneity. Calexcitin is a 22 kDa calcium-binding protein that becomes up-regulated in invertebrates following Pavlovian conditioning and is likely to be involved in signal transduction events associated with learning and memory. Recombinant squid calexcitin has been crystallized using the hanging-drop vapour-diffusion technique in the orthorhombic space group P2(1)2(1)2(1). The unit-cell parameters of a = 46.6, b = 69.2, c = 134.8 A suggest that the crystals contain two monomers per asymmetric unit and have a solvent content of 49%. This crystal form diffracts X-rays to at least 1.8 A resolution and yields data of high quality using synchrotron radiation.
authors.affiliation: School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, England.
authors.forename: G D E
authors.initials: GD
authors.lastname: Beaven
authors.forename: P T
authors.initials: PT
authors.lastname: Erskine
authors.forename: J N
authors.initials: JN
authors.lastname: Wright
authors.forename: F
authors.initials: F
authors.lastname: Mohammed
authors.forename: R
authors.initials: R
authors.lastname: Gill
authors.forename: S P
authors.initials: SP
authors.lastname: Wood
authors.forename: J
authors.initials: J
authors.lastname: Vernon
authors.forename: K P
authors.initials: KP
authors.lastname: Giese
authors.forename: J B
authors.initials: JB
authors.lastname: Cooper
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D018076:DNA, Complementary / Q000378:metabolism; D049832:Decapodiformes; D004058:Diffusion; D004926:Escherichia coli / Q000378:metabolism; D007858:Learning; D049834:Loligo / Q000737:chemistry*; D008568:Memory; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D015854:Up-Regulation; D014961:X-Ray Diffraction
chemical_list: D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D002118:Calcium