Crystallization and preliminary X-ray crystallographic analysis of a full-length active form of the Cry4Ba toxin from Bacillus thuringiensis.

To obtain a complete structure of the Bacillus thuringiensis Cry4Ba mosquito-larvicidal protein, a 65 kDa functional form of the Cry4Ba-R203Q mutant toxin was generated for crystallization by eliminating the tryptic cleavage site at Arg203. The 65 kDa trypsin-resistant fragment was purified and crystallized using the sitting-drop vapour-diffusion method. The crystals belonged to the rhombohedral space group R32, with unit-cell parameters a = b = 184.62, c = 187.36 Å. Diffraction data were collected to at least 2.07 Å resolution using synchrotron radiation and gave a data set with an overall R_merge of 9.1% and a completeness of 99.9%. Preliminary analysis indicated that the asymmetric unit contained one molecule of the active full-length mutant, with a V_M coefficient and solvent content of 4.33 ų Da⁻¹ and 71%, respectively. [ABSTRACT FROM AUTHOR]