title: Crystallization and preliminary crystallographic studies of Schizolobium parahyba chymotrypsin inhibitor (SPCI) at 1.8 A resolution.
abstract: SPCI, a Kunitz-type chymotrypsin inhibitor, is a 180-amino-acid polypeptide isolated from Schizolobium parahyba seeds. This inhibitor has been characterized as a highly stable protein over a broad pH and temperature range. SPCI was crystallized using a solution containing 0.1 M sodium acetate trihydrate buffer pH 4.6, 33%(v/v) PEG 2000 and 0.2 M ammonium sulfate. Data were collected to 1.80 A resolution from a single crystal of SPCI under cryogenic conditions. The protein crystallized in space group P2(1)2(1)2, with unit-cell parameters a = 40.01, b = 71.58, c = 108.68 A and an R(merge) of 0.052. The structure of SPCI has been solved by molecular replacement using the known structure of the Kunitz-type trypsin inhibitor from Delonix regia (PDB code 1r8n) as the search model.
authors.affiliation: Laboratório de Biofísica, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília-DF, 70910-900, Brazil.
authors.forename: Rozeni Chagas Lima
authors.initials: RC
authors.lastname: Teles
authors.forename: Gisele Ferreira
authors.initials: GF
authors.lastname: Esteves
authors.forename: Marcus Aurélio Miranda
authors.initials: MA
authors.lastname: Araújo
authors.forename: Carlos
authors.initials: C
authors.lastname: Bloch
authors.forename: João Alexandre Ribeiro Gonçalves
authors.initials: JA
authors.lastname: Barbosa
authors.forename: Sonia Maria
authors.initials: SM
authors.lastname: de Freitas
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D007887:Fabaceae / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D015842:Serine Proteinase Inhibitors / Q000737:chemistry*
chemical_list: C096591:Chymotrypsin inhibitor protein, Schizolobium parahybum; D010940:Plant Proteins; D015842:Serine Proteinase Inhibitors