Crystallization and preliminary X-ray crystallographic analysis of the heterodimeric crotoxin complex and the isolated subunits crotapotin and phospholipase A2.

Crotoxin, a potent neurotoxin from the venom of the South American rattlesnake Crotalus durissus terrificus, exists as a heterodimer formed between a phospholipase A(2) and a catalytically inactive acidic phospholipase A(2) analogue (crotapotin). Large single crystals of the crotoxin complex and of the isolated subunits have been obtained. The crotoxin complex crystal belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 38.2, b = 68.7, c = 84.2 A, and diffracted to 1.75 A resolution. The crystal of the phospholipase A(2) domain belongs to the hexagonal space group P6(1)22 (or its enantiomorph P6(5)22), with unit-cell parameters a = b = 38.7, c = 286.7 A, and diffracted to 2.6 A resolution. The crotapotin crystal diffracted to 2.3 A resolution; however, the highly diffuse diffraction pattern did not permit unambiguous assignment of the unit-cell parameters.

Crystallization, data collection and phasing of black-eyed pea trypsin/chymotrypsin inhibitor in complex with bovine beta-trypsin.

The black-eyed pea trypsin and chymotrypsin inhibitor (BTCI) is a Bowman-Birk-type inhibitor from Vigna unguiculata seeds. A complex of BTCI with bovine beta-trypsin was crystallized by the hanging-drop vapour-diffusion method with ammonium sulfate as precipitant. Crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 59.3, b = 61.8, c = 80.0 A. Diffraction data were collected to 2.36 A resolution and were processed to give an overall R(sym) of 0.137. The Matthews coefficient for one complex per asymmetric unit is 2.2 A(3) Da(-1), with a corresponding solvent content of 43%. After molecular replacement and initial refinement, the model gives an R(cryst) of 0.361 and an R(free) of 0.432.

Crystallization and preliminary X-ray diffraction analysis of a novel trypsin inhibitor from seeds of Copaifera langsdorffii.

A novel trypsin inhibitor isolated from seeds of Copaifera langsdorffii was purified to homogeneity and crystallized. Crystals suitable for X-ray analysis were grown using the hanging-drop vapour-diffusion method at 291 K in sodium acetate buffer at pH values near 4.3 using PEG 4000 as precipitant. The crystals presented symmetry compatible with the space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = b = 58.71, c = 93.75 A, and diffracted to 1.83 A resolution at the synchrotron source.

Crystallization and preliminary X-ray study of haem-binding protein from the bloodsucking insect Rhodnius prolixus.

Rhodnius haem-binding protein (RHBP) from the bloodsucking insect Rhodnius prolixus, a 15 kDa protein, has been crystallized using polyethylene glycol as a precipitant. X-ray diffraction data have been collected at a synchrotron source. The crystals belong to the space group P4(1(3))2(1)2, with unit-cell parameters a = b = 64.98, c = 210.68 A, and diffract beyond 2.6 A resolution.