Immobilization of Malarial (<i>Plasmodium falciparum</i>) Dihydrofolate Reductase for the Selection of Tight-Binding Inhibitors from Combinatorial Library
作者:Chawanee Thongpanchang、Supannee Taweechai、Sumalee Kamchonwongpaisan、Yongyuth Yuthavong、Yodhathai Thebtaranonth
DOI:10.1021/ac070215s
日期:2007.7.1
A simple procedure for selection of tight-binding inhibitors of mutant dihydrofolate reductases from Plasmodium falciparum (PfDHFRs) based on preferential binding to the enzyme immobilized on a Sepharose column has been described. PfDHFRs with a cysteine residue at the C-terminal have been prepared in order to immobilize to a thiopropyl-Sepharose gel via S−S linkage. The amount of immobilized DHFRs was estimated to be 4−5 mg/g of dried gel, and the activities of bound DHFRs were comparable to that of free enzymes. The prepared immobilized enzyme has been used for the selection of tight-binding inhibitors from combinatorial libraries, based on the affinities of each ligand with the enzyme. Free ligands were then identified and analyzed quantitatively by high-performance liquid chromatography−mass spectrometry, and the components with high binding affinity of the library could thus be realized. Results could be confirmed by quantitative analysis of the bound ligands released from the enzyme by guanidine hydrochloride treatment.
已经描述了一种基于优先结合固定在Sepharose柱上的酶的选择突变型恶性疟原虫二氢叶酸还原酶(PfDHFRs)的紧密结合抑制剂的简单程序。为了通过S-S键固定到硫丙基-Sepharose凝胶上,制备了在C末端具有半胱氨酸残基的PfDHFRs。估计固定化的DHFRs量为4-5毫克/克干燥凝胶,并且与自由酶的活性相当。制备的固定化酶已被用于从组合库中选择紧密结合抑制剂,基于每个配体与酶的亲和力。然后通过高效液相色谱-质谱法识别和定量分析自由配体,从而实现库中具有高结合亲和力的成分。结果可以通过定量分析通过盐酸胍处理从酶中释放的结合配体来确认。