title: Purification, crystallization and preliminary X-ray analysis of mexicain.
abstract: Mexicain is a 23.7 kDa papain-like cysteine protease from the tropical plant Jacaratia mexicana. Extracted as a mix of proteases from the latex of the fruit, mexicain is isolated after cation-exchange chromatography as the most abundant product. The purified product inhibited with E-64 was crystallized by sitting-drop vapour diffusion in the presence of ethanolamine. Cryoprotected crystals diffracted X-rays from a home source to 1.98 A and belong to the monoclinic space group P2(1), with unit-cell parameters a = 57.36, b = 90.45, c = 80.39 A, beta = 92.64 degrees . The asymmetric unit contains four molecules of mexicain, with a corresponding crystal volume per protein weight (V(M)) of 2.24 A(3) Da(-1) and a solvent content of 45% by volume. A molecular-replacement model has been determined and refinement is in progress.
authors.affiliation: Unidad Profesional Interdisciplinaria de Biotecnología, IPN, México DF, México.
authors.forename: M C
authors.initials: MC
authors.lastname: Oliver-Salvador
authors.forename: L A
authors.initials: LA
authors.lastname: González-Ramírez
authors.forename: J A
authors.initials: JA
authors.lastname: Gavira
authors.forename: M
authors.initials: M
authors.lastname: Soriano-García
authors.forename: J M
authors.initials: JM
authors.lastname: García-Ruiz
mesh_terms: D031241:Caricaceae / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000302:isolation & purification; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D010940:Plant Proteins; D003546:Cysteine Endopeptidases