Fujishima Y, Nordlund P, Pelosi G, Schofield C J, Cole S J, Baldwin J E, Hajdu J
Laboratory of Molecular Biophysics, University of Oxford, U.K.
J Mol Biol. 1994 Oct 7;242(5):712-4. doi: 10.1006/jmbi.1994.1622.
Recombinant isopenicillin N synthase from Cephalosporium acremonium was expressed in Escherichia coli and the protein was purified. After nearly 5000 crystallization trials, the apo enzyme was crystallized by the hanging drop vapour diffusion technique, using polyethylene glycol and lithium sulphate as precipitants. Two crystal forms have been obtained with either octahedral or elongated prismatic habits. The larger octahedral crystals (0.1 mm over-all dimensions) belong to space group I4 with unit cell dimensions of a = b = 124.7 A, c = 156.9 A, and diffract X-rays to about 3.5 A resolution at synchrotrons. The crystallographic asymmetric unit contains a dimer.
来自顶头孢霉的重组异青霉素N合酶在大肠杆菌中表达并进行了蛋白纯化。经过近5000次结晶试验后，采用悬滴气相扩散技术，以聚乙二醇和硫酸锂作为沉淀剂，使脱辅基酶结晶。获得了两种晶体形态，分别为八面体习性和细长棱柱体习性。较大的八面体晶体（整体尺寸为0.1毫米）属于空间群I4，晶胞参数为a = b = 124.7 Å，c = 156.9 Å，在同步加速器上可将X射线衍射至约3.5 Å分辨率。晶体学不对称单元包含一个二聚体。
