Thamwiriyasati Niramon, Sakdee Somsri, Chuankhayan Phimonphan, Katzenmeier Gerd, Chen Chun Jung, Angsuthanasombat Chanan
Laboratory of Molecular Biophysics and Structural Biochemistry, Bacterial Protein Toxin Research Unit, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Jun 1;66(Pt 6):721-4. doi: 10.1107/S1744309110015344. Epub 2010 May 29.
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 A. Diffraction data were collected to at least 2.07 A 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 A(3) Da(-1) and 71%, respectively.
为获得苏云金芽孢杆菌Cry4Ba杀蚊幼虫蛋白的完整结构，通过消除位于精氨酸203处的胰蛋白酶切割位点，产生了一种65 kDa的Cry4Ba-R203Q突变毒素功能形式用于结晶。使用坐滴气相扩散法对65 kDa的抗胰蛋白酶片段进行纯化和结晶。晶体属于菱面体空间群R32，晶胞参数a = b = 184.62，c = 187.36 Å。使用同步辐射收集衍射数据至至少2.07 Å分辨率，得到一个总体R(merge)为9.1%、完整性为99.9%的数据集。初步分析表明，不对称单元包含一个活性全长突变体分子，V(M)系数和溶剂含量分别为4.33 ų Da⁻¹和71%。
