Hlinková V, Urbániková L, Krajcíková D, Sevcík J
Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 842 51 Bratislava, Slovak Republic.
Acta Crystallogr D Biol Crystallogr. 2001 May;57(Pt 5):737-9. doi: 10.1107/s0907444901003456. Epub 2001 Apr 24.
RNase Sa3 produced by Streptomyces aureofaciens strain CCM 3239 belongs to the T1 family of microbial ribonucleases. It is closely related both to RNase Sa, studied in detail earlier, and to RNase Sa2 produced by the same microorganism. The most important property of RNase Sa3 is the relatively high cytotoxic activity, which was not observed for RNase Sa and Sa2. Recombinant RNase Sa3 was overexpressed in Escherichia coli and purified to high homogeneity. The hanging-drop vapour-diffusion method was used for crystallization. The two crystal forms are trigonal P3(1)21 and tetragonal P4(1)2(1)2, with unit-cell parameters a = b = 64.7, c = 69.6 A, gamma = 120 degrees and a = b = 34.0, c = 147.2 A, respectively. They diffract to 2.0 and to 1.7 A resolution, respectively, using synchrotron radiation. The asymmetric units of crystal forms I and II contain one molecule of the enzyme, which corresponds to V(M) = 3.8 A(3) Da(-1) with a solvent content of 68% and V(M) = 1.9 A(3) Da(-1) with a solvent content of 37%, respectively.
由金色链霉菌菌株CCM 3239产生的核糖核酸酶Sa3属于微生物核糖核酸酶的T1家族。它与之前详细研究过的核糖核酸酶Sa以及由同一微生物产生的核糖核酸酶Sa2密切相关。核糖核酸酶Sa3最重要的特性是相对较高的细胞毒性活性，而核糖核酸酶Sa和Sa2则未观察到这种活性。重组核糖核酸酶Sa3在大肠杆菌中过表达并纯化至高度均一。采用悬滴气相扩散法进行结晶。两种晶体形式分别为三方晶系P3(1)21和四方晶系P4(1)2(1)2，晶胞参数分别为a = b = 64.7，c = 69.6 Å，γ = 120°和a = b = 34.0，c = 147.2 Å。使用同步辐射，它们分别衍射到2.0 Å和1.7 Å的分辨率。晶体形式I和II的不对称单元各包含一个酶分子，其对应的V(M)分别为3.8 ų Da⁻¹，溶剂含量为68%，以及V(M)为1.9 ų Da⁻¹，溶剂含量为37%。
