在已报道的R-藻红蛋白金(AUC4)和汞(PCMS)重原子衍生物的基础上,又得到了含重金属铂(PTC4)和汞(PHMH)的与R-藻红蛋白母体同晶型的另外2种重原子衍生物。使用全部4种重原子衍生物联合相位(MIR)的品质因子(figure of merit)为0.70.经溶剂过滤法处理,相位得到了很大改善,总的品质因子增加到0.86,从已改善的MIR相位计算的电子密度图上可以清晰的观测到R-藻红蛋白亚基间的配置和分子的轮廓。
The basic phospholipase A2 from the venom of Agkistrodon halys pallas possesses the ability to cause hemolysis in contrast to the other two phospholipase A2 from the same venom. A new form of crystals of this enzyme was grown. The crystals belong to space group of P212121 with unit cell parameters of a=9. 175nm, b=10.080nm , c=2.287nm.The crystals diffract to high resolution, and are suitable for detailed structural studies. The data were collected up to 0.25nm resolutiorl using synchrotron radiation-imaging plate-Weissenberg camera system. Preliminary analysis reveals the presence of two molecules in the asymmetric uint and the molecule may pack with the smallest dimension approximately parallel to the c axis. The new crystal form is more attractive than the monoclinic one previously reported for crystallographic structure determination as it contains fewermolecules in the asymmetric unit.
