title: Crystallization and preliminary X-ray crystallographic analysis of the C-terminal domain of guanylate kinase-associated protein from Rattus norvegicus.
abstract: Guanylate kinase-associated protein (GKAP) is a scaffolding protein that plays a role in protein-protein interactions at the synaptic junction such as linking the NMDA receptor-PSD-95 complex to the Shank-Homer complex. In this study, the C-terminal helical domain of GKAP from Rattus norvegicus was purified and crystallized by the vapour-diffusion method. To improve the diffraction quality of the GKAP crystals, a flexible loop in GKAP was truncated and an MBP (maltose-binding protein)-GKAP fusion was constructed in which the last C-terminal helix of MBP is fused to the N-terminus of the GKAP domain. The MBP-GKAP crystals diffracted to 2.0 Å resolution using synchrotron radiation. The crystal was orthorhombic, belonging to space group P2₁2₁2, with unit-cell parameters a=99.1, b=158.7, c=65.5 Å. The Matthews coefficient was determined to be 2.44 Å3 Da(-1) (solvent content 49.5%) with two molecules in the asymmetric unit. Initial attempts to solve the structure by molecular replacement using the MBP structure were successful.
authors.affiliation: College of Pharmacy, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Junsen
authors.initials: J
authors.lastname: Tong
authors.affiliation: College of Pharmacy, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Huiseon
authors.initials: H
authors.lastname: Yang
authors.affiliation: College of Pharmacy, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Im
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D058619:Maltose-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000074407:SAP90-PSD95 Associated Proteins; D016415:Sequence Alignment
chemical_list: D058619:Maltose-Binding Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D000074407:SAP90-PSD95 Associated Proteins
keywords: GKAP; Rattus norvegicus; maltose-binding protein; scaffolding protein