State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, P R China.
Org Biomol Chem. 2012 May 21;10(19):3913-23. doi: 10.1039/c2ob07076f. Epub 2012 Apr 5.
Hypoxia inducible factor 1 (HIF-1) is central to the hypoxic response in mammals. HIF-1α prolyl hydroxylase 3 (PHD3) degrades HIF through the hydroxylation of HIF-1α. Inhibition of PHD3 activity is crucial for up-regulating HIF-1α levels, thereby acting as HIF-dependent diseases therapy. Macrocyclic polyamines which display high stability on iron-chelating may well inhibit the enzyme activity. Thus inhibition and interaction on catalytic PHD3 by four biologically active tetraazamacrocycles (1-4), which have two types of parent rings to chelate iron(ii) dissimilarly, were studied. The apparent IC(50) values of 2.56, 1.91, 5.29 and 2.44 μM, respectively, showed good inhibition potency of the four compounds. K(I) values were 7.86, 3.69, 1.59 and 2.92 μM for 1-4, respectively. Different inhibition actions of the two groups of compounds were identified. Circular dichroism (CD) and fluorescence spectrometries proved that one type of compound has significant effects on protein conformation while another type does not. Computational methodology was constructed to employ the equilibrium geometry of enzyme active site with the presence of substrate competitive inhibitor. Iron(ii) coordination in the active site by inhibitors of this kind induces conformational change of the enzyme and blocks substrate binding.
缺氧诱导因子 1（HIF-1）是哺乳动物缺氧反应的核心。HIF-1α脯氨酰羟化酶 3（PHD3）通过 HIF-1α 的羟化作用降解 HIF。抑制 PHD3 活性对于上调 HIF-1α 水平至关重要，从而作为 HIF 依赖性疾病的治疗方法。显示出对铁螯合高稳定性的大环聚胺很可能抑制酶活性。因此，研究了四种具有两种不同类型母体环以不同方式螯合铁（ii）的生物活性四氮大环（1-4）对催化 PHD3 的抑制和相互作用。四个化合物的表观 IC（50）值分别为 2.56、1.91、5.29 和 2.44 μM，显示出良好的抑制效力。K（I）值分别为 7.86、3.69、1.59 和 2.92 μM。两种类型的化合物具有不同的抑制作用。圆二色性（CD）和荧光光谱证明了一种类型的化合物对蛋白质构象有显著影响，而另一种类型则没有。构建了计算方法，以利用酶活性位点的平衡几何形状和底物竞争性抑制剂的存在。这类抑制剂在活性位点与铁（ii）的配位诱导酶的构象变化，并阻止底物结合。
