title: Crystallization, characterization, and preliminary crystallographic studies of mitochondrial carbamoyl phosphate synthetase I of Rana catesbeiana.
abstract: Carbamoyl phosphate synthetase I (ammonia; E C 6.3.4.16) was purified from the liver of Rana catesbeiana (bullfrog). Crystals of the protein have been obtained at 22 degrees C by the hanging drop vapor diffusion technique, with polyethylene glycol as precipitant. Tetragonal crystals of about 0.3 x 0.3 x 0.7 mm diffract at room temperature to at least 3.5 A using a conventional source and are stable to X-radiation for about 12 h. Therefore, these crystals are suitable for high resolution studies. The space group is P4(1)2(1)2 (or its enantiomorph P4(3)2(1)2), with unit cell dimensions a = b = 291.6 A and c = 189.4 A. Density packing considerations are consistent with the presence of 4-6 monomers (M(r) of the monomer, 160,000) in the asymmetric unit. Amino-terminal sequence of the enzyme and of a chymotryptic fragment of 73.7 kDa containing the COOH-terminus has been obtained. The extensive sequence identity with rat and human carbamoyl phosphate synthetase I indicates the relevance for mammals of structural data obtained with the frog enzyme.
authors.affiliation: Instituto de Investigaciones Citológicas de la Fundación Valenciana de Investigaciones Biomédicas (Centro Asociado del CSIC), Spain.
authors.forename: A
authors.initials: A
authors.lastname: Marina
authors.forename: J
authors.initials: J
authors.lastname: Bravo
authors.forename: I
authors.initials: I
authors.lastname: Fita
authors.forename: V
authors.initials: V
authors.lastname: Rubio
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000737:chemistry* / Q000302:isolation & purification; D006801:Humans; D008930:Mitochondria, Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D011092:Polyethylene Glycols / Q000737:chemistry; D011898:Ranidae; D051381:Rats; D016415:Sequence Alignment; D017421:Sequence Analysis; D014961:X-Ray Diffraction
chemical_list: D011092:Polyethylene Glycols; D002222:Carbamoyl-Phosphate Synthase (Ammonia)