Håkansson K, Wehnert A, Liljas A
Molecular Biophysics, Chemical Center, University of Lund, Sweden.
Acta Crystallogr D Biol Crystallogr. 1994 Jan 1;50(Pt 1):93-100. doi: 10.1107/S0907444993008790.
Metal-substituted crystals of human carbonic anhydrase II belonging to space group P2(1) with cell dimensions a = 42.7, b = 41.7, c = 73.0 A and beta = 104.6 degrees were analyzed crystallographically. The resolution limit ranged from 1.82 to 1.92 A with high completeness (86.2-90.7%). Cobalt(II)-substituted carbonic anhydrase has a tetrahedral coordination around the metal both at pH 6 and pH 7.8, similar to the native zinc enzyme. In contrast, the catalytically inactive copper(II), nickel(II) and manganese(II) derivatives showed increased coordination number around the metal ion. Whereas the copper is best described as penta-coordinated, the nickel and manganese are best described as hexa-coordinated. The results are briefly compared with spectroscopic observations and our current view on carbonic anhydrase catalysis.
对属于空间群P2(1)、晶胞参数a = 42.7、b = 41.7、c = 73.0 Å且β = 104.6°的人碳酸酐酶II的金属取代晶体进行了晶体学分析。分辨率极限在1.82至1.92 Å之间，完整性较高（86.2 - 90.7%）。钴(II)取代的碳酸酐酶在pH 6和pH 7.8时金属周围均具有四面体配位，类似于天然锌酶。相比之下，催化无活性的铜(II)、镍(II)和锰(II)衍生物在金属离子周围显示出增加的配位数。铜最好描述为五配位，而镍和锰最好描述为六配位。将结果与光谱观察结果以及我们目前对碳酸酐酶催化作用的观点进行了简要比较。
