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外文期刊>Acta crystallographica.Section D. Biological crystallography
>Molecular replacement in the 'twilight zone': structure determination of the non-haem iron oxygenase NovR from Streptomyces spheroides through repeated density modification of a poor molecular-replacement solution
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Molecular replacement in the 'twilight zone': structure determination of the non-haem iron oxygenase NovR from Streptomyces spheroides through repeated density modification of a poor molecular-replacement solution
Crystals of recombinant NovR (subunit MW = 29 924 Da; 270 amino acids), a non-haem iron oxygenase from Streptomyces spheroides, were grown by vapour diffusion. The protein crystallized in space group C2, with unit-cell parameters a = 86.69, b = 139.38, c = 100.82 angstrom, beta = 101.18 degrees. Native data were collected to a resolution of 2.1 angstrom from a single crystal at a synchrotron and a molecular-replacement solution was obtained using the program AMoRe. The starting phase information was very poor and did not permit model building. Phases were subsequently improved using a combination of fourfold averaging and very gradual phase extension in the program DM to yield an interpretable map. NovR belongs to a novel class of non-haem iron oxygenases that share sequence similarity with class II aldolases. It is predicted to perform two consecutive oxidative decarboxylation steps in the biosynthesis of the prenylated hydroxybenzoic acid moiety of the aminocoumarin antibiotic novobiocin.
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机译：晶体的重组11月(亚基29 MW = 924达;从链霉菌属球体都增长了蒸汽扩散。空间群C2,晶胞参数=86.69, b = 139.38, c = 100.82埃,β=101.18度。分辨率为2.1埃单晶在同步加速器和molecular-replacement解决方案是使用程序获得爱茉莉。开始阶段非常贫穷和信息不允许模型构建。随后使用相结合的改进四倍平均和渐进的阶段扩展程序中的DM产量可说明的地图。非血红素铁的加氧酶共享序列与二级醛缩酶相似。预测执行两个连续的氧化脱酸的生物合成步骤prenylated水杨酸的一部分aminocoumarin新生霉素抗生素。
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