Marina A, Bravo J, Fita I, Rubio V
Instituto de Investigaciones Citologicas, F.I.B. Centro Asociado del CSIC, Valencia, Spain.
J Mol Biol. 1994 Jan 28;235(4):1345-7. doi: 10.1006/jmbi.1994.1088.
Crystals of carbamate kinase (E.C.2.7.2.2) suitable for high resolution studies have been obtained, using the hanging drop vapour diffusion technique, with polyethylene glycol 8000 and NaCl as precipitants at pH 6.5 and a temperature of 4 degrees C. Crystals of about 0.3 mm x 0.2 mm x 0.2 mm in size diffract to at least 3.2 A resolution and are stable to X-radiation for more than ten hours. The space group is P2(1)2(1)2(1), with unit cell dimensions a = 84.5 A, b = 99.6 A, c = 173.3 A. Density packing considerations are consistent with the presence of four to five monomers (M(r) of the monomer = 33,000) in the asymmetric unit, two dimers or even a tetramer being favoured by the results of cross-linking experiments of the enzyme in solution.
利用悬滴气相扩散技术，以聚乙二醇8000和氯化钠作为沉淀剂，在pH 6.5和4℃温度条件下，已获得适用于高分辨率研究的氨基甲酸激酶（E.C.2.7.2.2）晶体。尺寸约为0.3mm×0.2mm×0.2mm的晶体衍射分辨率至少为3.2 Å，并且对X射线辐射稳定超过十小时。空间群为P2(1)2(1)2(1)，晶胞参数a = 84.5 Å，b = 99.6 Å，c = 173.3 Å。密度堆积分析结果与不对称单元中存在四到五个单体（单体的相对分子质量M(r)= 33,000）相一致，溶液中该酶的交联实验结果表明两个二聚体甚至一个四聚体更受青睐。
