Fletcher R S, Arion D, Borkow G, Wainberg M A, Dmitrienko G I, Parniak M A
Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada.
Biochemistry. 1995 Aug 15;34(32):10106-12. doi: 10.1021/bi00032a002.
The carboxanilides UC84 and UC38 are nonnucleoside inhibitors of both the RNA-dependent and DNA-dependent DNA polymerase activities of HIV-1 reverse transcriptase (RT). We have previously shown that UC84 and UC38 bind to the same site as nevirapine but interact with different RT mechanistic forms, with UC84 preferentially binding to the RT-primer/template complex and UC38 binding only to the RT-primer/template-dNTP ternary complex [Fletcher, R. S., et al. (1995) Biochemistry 34, 4346-4353]. Here we demonstrate that combinations of UC84 and UC38 inhibit RT DNA polymerase activity in vitro in a synergistic manner. This synergy was noted primarily in reactions containing high concentrations of primer/template and Km levels of dNTP substrate and was independent of both primer/template identity and the molar ratio of UC84:UC38. Combination indices were in the range of 0.4-0.6, indicating substantial synergy in the inhibition of RT activity. More importantly, combinations of UC84 and UC38 also showed a high degree of synergy in inhibiting HIV-1 replication in both MT-4 and cord blood mononuclear cells. We believe this to be the first example of synergistic inhibition of HIV-1 RT by combinations of structurally related nonnucleoside inhibitors.
羧酰苯胺类化合物UC84和UC38是HIV-1逆转录酶（RT）的RNA依赖性和DNA依赖性DNA聚合酶活性的非核苷抑制剂。我们之前已经表明，UC84和UC38与奈韦拉平结合于同一位点，但与不同的RT机制形式相互作用，UC84优先结合RT-引物/模板复合物，而UC38仅结合RT-引物/模板-dNTP三元复合物[弗莱彻，R.S.等人（1995年）《生物化学》34卷，4346 - 4353页]。在此我们证明，UC84和UC38的组合在体外以协同方式抑制RT DNA聚合酶活性。这种协同作用主要在含有高浓度引物/模板和Km水平的dNTP底物的反应中观察到，并且与引物/模板的种类以及UC84与UC38的摩尔比均无关。联合指数在0.4 - 0.6范围内，表明在抑制RT活性方面有显著的协同作用。更重要的是，UC84和UC38的组合在抑制MT - 4细胞和脐血单核细胞中的HIV - 1复制方面也表现出高度协同作用。我们认为这是结构相关的非核苷抑制剂组合对HIV - 1 RT进行协同抑制的首个实例。
