title: Optimization of crystals of an inhibitory antibody of urokinase plasminogen activator receptor (uPAR) with hydrogen peroxide and low protein concentration.
abstract: Optimization of protein crystal formation is often a necessary step leading to diffraction-quality crystals to enable collection of a full X-ray data set. Typical protein crystal optimization involves screening different components, e.g., pH, precipitants, and additives of the precipitant solution. Here we present an example using an inhibitory antibody of urokinase plasminogen activator receptor (uPAR) where such procedures did not yield diffracting crystals. In contrast, it was the treatment of the protein with hydrogen peroxide incubation and the protein concentration reduction that were found to be key factors in obtaining diffracting crystals. Final crystals diffracted to 1.75 A, and belong to orthorhombic P2(1)2(1)2(1) space group with unit cell parameters a = 37.162 A, b = 84.474 A, c = 134.030 A, and contain one molecule of Fab fragment of anti-uro kinase receptor antibody in the asymmetric unit.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, Fuzhou 350002, People's Republic of China.
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shi
authors.forename: Graham
authors.initials: G
authors.lastname: Parry
authors.forename: Liqing
authors.initials: L
authors.lastname: Chen
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Callahan
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Mazar
authors.forename: Mingdong
authors.initials: M
authors.lastname: Huang
mesh_terms: D000906:Antibodies / Q000737:chemistry* / Q000276:immunology*; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000276:immunology*; D055293:Receptors, Urokinase Plasminogen Activator
chemical_list: D000906:Antibodies; C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D006861:Hydrogen Peroxide