Djinovic-Carugo Kristina, Carugo Oliviero
Max F. Perutz Laboratories, University of Vienna, 5 Campus Vienna Biocenter, A-1030, Austria; Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1000 Ljubljana, Slovenia.
Department of Chemistry, University of Pavia, Viale Taramelli 12, I-27100 Pavia, Italy.
J Inorg Biochem. 2015 Feb;143:69-76. doi: 10.1016/j.jinorgbio.2014.12.005. Epub 2014 Dec 11.
With its about 100,000 three-dimensional structures, the Protein Data Bank is a copious source of information: it contains also some hundreds of structures of macromolecules complexed with lanthanide cations, which are examined here. These cations, which are found in a wide variety of protein types, were introduced to determine the structures, by exploiting their anomalous dispersion (in crystallographic studies, where they are also used as crystallization additives) or the paramagnetic pseudocontact shifts (in NMR analyses). The coordination numbers in the first coordination sphere are very variable, though they tend to be close to those that are observed in small molecules or in water solution. The coordination polyhedra are also quite variable as it can be expected for large cations. Interestingly, lanthanide cations are frequently observed in packing bridges between symmetry equivalent molecules in crystals, where they tend to form polynuclear complexes, with up to seven cations bridged by water/hydroxide ligands.
蛋白质数据库拥有约10万个三维结构，是一个丰富的信息源：它还包含数百个与镧系阳离子复合的大分子结构，本文将对这些结构进行研究。这些阳离子存在于多种蛋白质类型中，通过利用它们的反常色散（在晶体学研究中，它们也用作结晶添加剂）或顺磁假接触位移（在核磁共振分析中）来确定结构。第一配位层中的配位数变化很大，不过它们往往接近在小分子或水溶液中观察到的配位数。正如对大阳离子所预期的那样，配位多面体也变化很大。有趣的是，在晶体中对称等效分子之间的堆积桥中经常观察到镧系阳离子，在那里它们倾向于形成多核配合物，多达七个阳离子由水/氢氧根配体桥连。
