Guarné A, Kirchweger R, Verdaguer N, Liebig H D, Blaas D, Skern T, Fita I
Centre d'Investigació i Desenvolupament (CSIC), Barcelona, Spain.
Protein Sci. 1996 Sep;5(9):1931-3. doi: 10.1002/pro.5560050921.
Different crystal forms of the C23A mutant from the leader proteinase of foot-and-mouth disease virus were obtained by the hanging drop vapor diffusion technique, using MgCl2 and PEG 6000 as precipitants. Well-developed crystals, with cubic morphology growing to approximately 1.0 mm3 in size, presented a large unit cell parameter of 274.5 A and diffracted to, at most, 5 A resolution. A second type of crystal had a tetragonal appearance and these were obtained in droplets soaked in a silica gel matrix. These crystals, with an approximate size of 0.3 X 0.3 X 0.7 mm3, diffracted to approximately 4.0 A resolution, but presented a strong anisotropic mosaicity around the longest crystal axis. Crystals with a needlelike morphology and reaching sizes of about 0.2 X 0.3 X 1.2 mm3 diffracted beyond 3.5 A resolution and were stable to X-ray radiation for approximately one day when using a conventional source at room temperature. These crystals are orthorhombic with space group I222 (or I2(1)2(1)2(1)) and unit cell dimensions a = 65.9 A, b = 104.3 A, and c = 124.0 A, and appear well suited for high-resolution studies. Density packing considerations are consistent with the presence of two molecules in the asymmetric unit and a solvent content of approximately 54%.
采用悬滴气相扩散技术，以MgCl2和聚乙二醇6000（PEG 6000）作为沉淀剂，获得了口蹄疫病毒前导蛋白酶C23A突变体的不同晶体形式。发育良好的立方形态晶体，大小生长至约1.0 mm3，呈现出274.5 Å的大晶胞参数，衍射极限为5 Å分辨率。第二种晶体呈四方外观，是在浸泡于硅胶基质的液滴中获得的。这些晶体大小约为0.3×0.3×0.7 mm3，衍射极限约为4.0 Å分辨率，但在最长晶轴周围呈现出强烈的各向异性镶嵌性。针状形态的晶体大小约为0.2×0.3×1.2 mm3，衍射极限超过3.5 Å分辨率，在室温下使用常规光源时，对X射线辐射稳定约一天。这些晶体为正交晶系，空间群为I222（或I2(1)2(1)2(1)），晶胞尺寸a = 65.9 Å，b = 104.3 Å，c = 124.0 Å，似乎非常适合进行高分辨率研究。密度堆积考虑与不对称单元中存在两个分子以及约54%的溶剂含量一致。
