Macieira Sofia, Martins Berta M, Huber Robert
Max-Planck-Institut für Biochemie, Abt. Strukturforschung, Am Klopferspitz, 18-a, 82152, Martinsried, Germany.
FEMS Microbiol Lett. 2003 Sep 12;226(1):31-7. doi: 10.1016/S0378-1097(03)00531-7.
Coproporphyrinogen-III oxidase (CPO) catalyses the conversion of coproporphyrinogen-III to protoporphyrinogen-IX in the haem biosynthetic pathway, and its deficient activity is associated with human hereditary coproporphyria. The 47% sequence identity between the oxygen-dependent CPO from Escherichia coli and its human counterpart makes the bacterial enzyme a good model system for structural studies of this disease. Therefore, we overexpressed and purified to homogeneity the oxygen-dependent CPO from E. coli and its selenomethionine derivative fused with a His(6)-tag. Both preparations showed a specific activity of 37500 U mg(-1), had a subunit molecular mass of 35 kDa and behaved as a compact shaped dimer. First crystallisation trials produced plate-shaped diffracting crystals.
粪卟啉原III氧化酶（CPO）在血红素生物合成途径中催化粪卟啉原III转化为原卟啉原IX，其活性不足与人类遗传性粪卟啉病相关。来自大肠杆菌的氧依赖性CPO与其人类对应物之间47%的序列同一性，使得该细菌酶成为研究这种疾病结构的良好模型系统。因此，我们对来自大肠杆菌的氧依赖性CPO及其与His(6)标签融合的硒代甲硫氨酸衍生物进行了过表达并纯化至同质。两种制剂均显示出37500 U mg(-1)的比活性，亚基分子量为35 kDa，表现为紧密的二聚体形式。首次结晶试验产生了板状衍射晶体。
