Rocha Joana, Granja Ana Teresa, Sá-Correia Isabel, Fialho Arsénio, Frazão Carlos
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Jan 1;66(Pt 1):69-72. doi: 10.1107/S174430910904929X. Epub 2009 Dec 25.
Gellan gum, a commercial gelling agent produced by Sphingomonas elodea ATCC 31461, is a high-value microbial exopolysaccharide. UDP-glucose dehydrogenase (UGD; EC 1.1.1.22) is responsible for the NAD-dependent twofold oxidation of UDP-glucose to UDP-glucuronic acid, one of the key components for gellan biosynthesis. S. elodea ATCC 31461 UGD, termed UgdG, was cloned, expressed, purified and crystallized in native and SeMet-derivatized forms in hexagonal and tetragonal space groups, respectively; the crystals diffracted X-rays to 2.40 and 3.40 A resolution, respectively. Experimental phases were obtained for the tetragonal SeMet-derivatized crystal form by a single-wavelength anomalous dispersion experiment. This structure was successfully used as a molecular-replacement probe for the hexagonal crystal form of the native protein.
结冷胶是由伊乐藻鞘氨醇单胞菌ATCC 31461产生的一种商业凝胶剂，是一种高价值的微生物胞外多糖。尿苷二磷酸葡萄糖脱氢酶（UGD；EC 1.1.1.22）负责将尿苷二磷酸葡萄糖进行依赖于烟酰胺腺嘌呤二核苷酸的两步氧化反应，生成尿苷二磷酸葡萄糖醛酸，这是结冷胶生物合成的关键成分之一。伊乐藻鞘氨醇单胞菌ATCC 31461的UGD（称为UgdG）被克隆、表达、纯化，并分别以天然形式和硒代甲硫氨酸衍生形式在六方和四方空间群中结晶；这些晶体分别将X射线衍射到2.40埃和3.40埃的分辨率。通过单波长反常色散实验获得了四方硒代甲硫氨酸衍生晶体形式的实验相位。该结构成功地用作天然蛋白质六方晶体形式的分子置换探针。
