title: Crystallization, data collection and phasing of infestin 4, a factor XIIa inhibitor.
abstract: Infestin is a protein from Triatoma infestans (kissing bug) composed of seven Kazal-type domains that is further processed to yield several serine protease inhibitors with varying specificities. Infestins 3 and 4 are the last two domains of the infestin gene and are found in vivo in the insect's anterior midgut. The last domain, infestin 4, has been cloned, expressed and purified. Here, the crystallization of infestin 4 using the sitting-drop vapour-diffusion method with PEG 8000 as precipitant is described. Crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 25.89, b = 45.64, c = 57.41 A. X-ray diffraction data were collected to a maximum resolution of 1.8 A using a synchrotron-radiation source. Initial phases were calculated by molecular replacement using an edited rhodniin molecule as the search model. Structure refinement is in progress.
authors.affiliation: Departamento de Bioquímica, Escola Paulista de Medicina, UNIFESP-EPM, São Paulo, SP, Brazil.
authors.forename: I T N
authors.initials: IT
authors.lastname: Campos
authors.forename: B G
authors.initials: BG
authors.lastname: Guimarães
authors.forename: F J
authors.initials: FJ
authors.lastname: Medrano
authors.forename: A S
authors.initials: AS
authors.lastname: Tanaka
authors.forename: J A R G
authors.initials: JA
authors.lastname: Barbosa
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D019476:Insect Proteins / Q000737:chemistry*; D014224:Triatoma / Q000737:chemistry*
chemical_list: D001798:Blood Proteins; D019476:Insect Proteins; C053635:factor XIIa inhibitor; C467902:infestin protein, Triatoma infestans