Combinatorial library of asymmetric metal complexes and lead discovery for protein surface recognition

小型有机试剂对蛋白质-蛋白质相互作用的调节仍然是一个困难的挑战，因为这种相互作用涉及到大的埋藏表面的界面面积。这个项目的目标是构建一个稳定的低分子模块组装，它由合适的官能团组成，用于与靶向蛋白表面的互补结合。合成了一系列在联吡啶配体的4，4‘-位含有不同官能团的三联吡啶Ru配合物，并利用发色底物对α-胰凝乳酶的抑制活性进行了筛选，从而可以进行动力学酶试验。其中，含有苯丙氨酸残基的络合物显示出最好的抑制活性(50 pm时抑制率为73%)，而含有来自赖氨酸的阳离子电荷残基的络合物没有活性，这表明络合物与靠近…的蛋白质表面之间存在互补的静电相互作用活性部位越多，抑制作用越强。为了进一步测试这一策略以检测蛋白质的结构信息，如不对称和手性环境，我们应用了一种动态组合策略，使用Fe(II)，它可以作为中心金属，具有更快的配体交换速度，与本研究制备的一系列吡啶配体一起。当含谷氨酸(BpyGlu)和含赖氨酸(LysGlu)的吡啶与氯化铁(II)的摩尔比为1：1时，四种同分异构体的混合物有望以1：3：3：1的比例生成。用该混合液处理等电点为7的凝血酶时，其抑制效果比Fe(BpyGlu)3或Fe(BpyLys)3分别为100%和100%。这一结果表明，不对称络合物Fe(BpyGlu)(BpyLys)2或Fe(BpyGlu)2(BpyLys)具有比相应的对称络合物更高的缓蚀活性。我们相信，金属络合物文库将为蛋白质表面识别提供有用的线索发现工具，而蛋白质表面识别应该更容易受到不对称抑制剂的影响。较少

Modulation of protein-protein interactions by small organic agents still remains a difficult challenge due to the large interfacial areas of buried surface involved in such interactions. The goal of this project is to construct a stable assembly of low-molecular-weight modules that consist of appropriate functional groups for complementary binding to the targeting protein surfaces. A series of trisbipyridne ruthenium complexes consisting various functional group at 4, 4'-position of the bipyridine ligands was synthesized, and was screened for inhibition activity against alpha-chymotrypsin using the chromogenic substrate, which allows us to run the kinetic enzyme assay. Among them, the complex bearing phenylalanine residues showed the best inhibition activity (73% inhibition at 50 pM), whereas the one having cationic charged residue derived from lysines showed no activity, suggesting that the complementary electrostatic interaction in between the complex and the protein surface near the … More active site remarkably dictates the inhibition potency. For further test in this strategy to detect the protein structural information such as asymmetrical and chiral environment, we applied a dynamic combinatorial strategy using Fe (II), which can be a central metal with faster ligand exchanging rate, with the series of pyridine ligands prepared in this study. When 1:1 molar ratio of Glu-containing (bpyGlu) and Lys-containing (LysGlu) pyridines are mixed with iron(II) chloride, a mixture of four isomeric complexes is expected to yield in 1:3:3:1 ratio. When thrombin (pI=7) was treated with the mixture solution, the activity was suppressed more effectively than 100% of Fe(bpyGlu)3 or Fe(bpyLys)3, respectively. This result suggested that asymmetric complex, either Fe(bpyGlu) (bpyLys)2 or Fe(bpyGlu)2(bpyLys) possess higher inhibition activity than the corresponding symmetric complex. We believe that the metal complex library would provide a useful tool for the lead discovery for protein surface recognition, which should be more vulnerable with asymmetric inhibitors. Less