Matoba Kazuaki, Shiba Tomoo, Takeuchi Tsutomu, Sibley L David, Seiki Makiko, Kikyo Fumi, Horiuchi Toshio, Asai Takashi, Harada Shigeharu
Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Nov 1;66(Pt 11):1445-8. doi: 10.1107/S1744309110032136. Epub 2010 Oct 28.
The nucleoside triphosphate hydrolases that are produced by Neospora caninum (NcNTPase) and Toxoplasma gondii (TgNTPase-I) have a different physiological function from the ubiquitous ecto-ATPases. The recombinant enzymes were crystallized at 293 K using polyethylene glycol 3350 as a precipitant and X-ray diffraction data sets were collected for NcNTPase (to 2.8 Å resolution) and TgNTPase-I (to 3.1 Å resolution) at 100 K using synchrotron radiation. The crystals of NcNTPase and TgNTPase-I belonged to the orthorhombic space group I222 (unit-cell parameters a = 93.6, b = 140.8, c = 301.1 Å) and the monoclinic space group P2(1) (unit-cell parameters a = 87.1, b = 123.5, c = 120.2 Å, β = 96.6°), respectively, with two NcNTPase (V(M) = 3.7 Å(3) Da(-1)) and four TgNTPase-I (V(M) = 2.7 Å(3) Da(-1)) molecules per asymmetric unit. SAD phasing trials using a data set (λ = 0.97904 Å) collected from a crystal of selenomethionylated NcNTPase gave an initial electron-density map of sufficient quality to build a molecular model of NcNTPase.
犬新孢子虫（NcNTPase）和刚地弓形虫（TgNTPase-I）产生的核苷三磷酸水解酶具有与普遍存在的胞外ATP酶不同的生理功能。使用聚乙二醇3350作为沉淀剂，在293K下使重组酶结晶，并在100K下使用同步辐射收集NcNTPase（分辨率为2.8Å）和TgNTPase-I（分辨率为3.1Å）的X射线衍射数据集。NcNTPase和TgNTPase-I的晶体分别属于正交空间群I222（晶胞参数a = 93.6，b = 140.8，c = 301.1Å）和单斜空间群P2(1)（晶胞参数a = 87.1，b = 123.5，c = 120.2Å，β = 96.6°），每个不对称单位分别含有两个NcNTPase（V(M) = 3.7Å(3)Da(-1)）和四个TgNTPase-I（V(M) = 2.7Å(3)Da(-1)）分子。使用从硒代甲硫氨酸化的NcNTPase晶体收集的数据集（λ = 0.97904Å）进行的SAD相位试验给出了质量足以构建NcNTPase分子模型的初始电子密度图。
