Liotard Brigitte, Sygusch Jurgen
Département de Biochemie, Université de Montréal, CP 6128, Succursale Centre-Ville, Montréal H3C 3J7, Canada.
Acta Crystallogr D Biol Crystallogr. 2004 Mar;60(Pt 3):528-30. doi: 10.1107/S0907444903028427. Epub 2004 Feb 25.
Tagatose-1,6-bisphosphate aldolase (EC 4.1.2.40) is situated at the branching of the tagatose-6-phosphate and Embden-Meyerhof-Parnas (glycolysis) metabolic pathways, where it catalyzes the reversible cleavage of tagatose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. The recombinant protein from Streptococcus pyogenes was overexpressed in Escherichia coli in its native and selenomethionine-derivative forms and purified using ion-exchange and hydrophobic interaction chromatography. Orthorhombic crystals suitable for structural analysis were obtained by the hanging-drop vapour-diffusion method for both isoforms. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 63.7, b = 108.1, c = 238.7 A for the native form and a = 64.1, b = 108.3, c = 239.8 A for the selenomethionine derivative. The asymmetric unit contains four protomers, corresponding to a crystal volume per protein weight (V(M)) of 2.8 A(3) Da(-1) and a solvent content of 56% by volume.
塔格糖-1,6-二磷酸醛缩酶（EC 4.1.2.40）位于磷酸塔格糖和糖酵解（Embden-Meyerhof-Parnas）代谢途径的分支处，在此它催化塔格糖-1,6-二磷酸可逆地裂解为磷酸二羟丙酮和3-磷酸甘油醛。化脓性链球菌的重组蛋白以其天然形式和硒代甲硫氨酸衍生形式在大肠杆菌中过表达，并通过离子交换和疏水相互作用色谱法进行纯化。通过悬滴气相扩散法获得了适用于结构分析的两种异构体的正交晶体。晶体属于空间群P2(1)2(1)2(1)，天然形式的晶胞参数为a = 63.7、b = 108.1、c = 238.7 Å，硒代甲硫氨酸衍生物的晶胞参数为a = 64.1、b = 108.3、c = 239.8 Å。不对称单元包含四个原体，对应于每蛋白质重量的晶体体积（V(M)）为2.8 Å(3) Da(-1)，溶剂含量为56%（体积）。
