De Paola C C, Bennett B, Holz R C, Ringe D, Petsko G A
The Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA.
Biochemistry. 1999 Jul 13;38(28):9048-53. doi: 10.1021/bi9900572.
Hydrolases containing two metal ions connected by a bridging ligand catalyze reactions important in carcinogensis, tissue repair, post-translational modification, control and regulation of biochemical pathways, and protein degradation. The aminopeptidase from Aeromonas proteolytica serves as a paradigm for the study of such bridged bimetallic proteases since its three-dimensional structure is known to very high resolution and its catalytic reaction is amenable to spectroscopic examination. Herein, we report the X-ray crystal structure at 1.9 A resolution of AAP complexed with 1-butaneboronic acid (BuBA). This structure suggests that this complex represents a snapshot of the proteolytic reaction in an arrested form between the Michaelis complex and the transition state. Comparison of the structure with spectroscopic and other data allows us to conclude that the apparently structurally symmetrical dizinc site is actually asymmetric electrostatically.
含有通过桥连配体连接的两个金属离子的水解酶催化在致癌作用、组织修复、翻译后修饰、生化途径的控制和调节以及蛋白质降解中重要的反应。来自解蛋白气单胞菌的氨肽酶可作为研究此类桥连双金属蛋白酶的范例，因为已知其三维结构具有非常高的分辨率，并且其催化反应适合进行光谱检查。在此，我们报告了与1-丁基硼酸（BuBA）复合的AAP在1.9埃分辨率下的X射线晶体结构。该结构表明，这种复合物代表了在米氏复合物和过渡态之间以停滞形式存在的蛋白水解反应的一个瞬间。将该结构与光谱数据和其他数据进行比较，使我们能够得出结论，表面上结构对称的双锌位点实际上在静电方面是不对称的。
