Crystallization of a nickel-containing superoxide dismutase and preliminary phase determination by MAD at the Ni K edge.
Crystallization of a nickel-containing superoxide dismutase and preliminary phase determination by MAD at the Ni K edge.
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含镍超氧化物歧化酶的结晶和通过 MAD 在 Ni K 边缘进行初步相测定。
DOI：
10.1107/s0907444902007345
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
K. Djinović Carugo
中科院分区：
文献类型：
--
作者：
J. Wuerges;J. Lee;Sa‐Ouk Kang;K. Djinović Carugo
Superoxide dismutases are metalloenzymes which catalyse the disproportion of superoxide radicals and thus play an important role in the protection of biomolecules from oxidative damage. Redox-active metal ions known to act as the catalytic centre of these enzymes are Cu, Mn or Fe. Recently, enzymes containing Ni have been found in various Streptomyces species, introducing a fourth type of metal ion to the superoxide dismutase family. NiSOD has been crystallized for the purpose of structure determination by X-ray crystallography using Ni as an anomalous scatterer in multiple-wavelength anomalous dispersion (MAD) experiments. Two crystal forms belonging to space group P2(1)2(1)2(1) and one belonging to space group R3 were obtained using ammonium sulfate as a precipitant. Patterson maps of one of the orthorhombic forms revealed the presence of pseudo-translation, which could be removed for the other orthorhombic form by using 10% glycerol in its crystallization conditions. In addition, this reduced the unit cell by half. Phase information which led to interpretable electron-density maps was derived from MAD data to 2.0 A resolution after density modification applying solvent flattening, histogram matching and NCS averaging. Phases were extended to 1.68 A resolution with a data set collected at a wavelength of 1 A. Model building based on the resulting electron-density maps is in progress.
