NONNUCLEOSIDE INHIBITORS OF HIV-1 REVERSE-TRANSCRIPTASE - NEVIRAPINE AS A PROTOTYPE DRUG
NONNUCLEOSIDE INHIBITORS OF HIV-1 REVERSE-TRANSCRIPTASE - NEVIRAPINE AS A PROTOTYPE DRUG
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DOI：
10.1089/aid.1992.8.145
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发表时间：
1992-02-01
影响因子：
1.5
通讯作者：
MERLUZZI, VJ
中科院分区：
文献类型：
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作者：
GROB, PM;WU, JC;MERLUZZI, VJ
奈韦拉平是一种双吡啶二氮卓酮，是一种高度特异性的HIV-1逆转录酶（RT）抑制剂，在酶试验中显示出IC 50 = 84 nM，在细胞培养中对HIV-1复制的IC 50 = 40 nM。这种非核苷抑制剂对核苷三磷酸无竞争性作用，使用奈韦拉平的叠氮类似物作为光亲和探针的研究表明，一个分子的抑制剂足以抑制一个分子的异源二聚体酶，并证明只有p66/p51异二聚体RT被该探针共价标记。当进行胰蛋白酶图谱分析时，Tyr 181和Tyr 188用探针标记，因此这些芳香族残基显然接近或实际上在奈韦拉平的RT结合位点内。通过使用对奈韦拉平不敏感的HIV-2 RT的相应残基在这些位置进行氨基酸取代，确定Tyr 181和Tyr 188参与/促进奈韦拉平结合的程度。任何一个位置的变化都显著降低了酶对奈韦拉平以及TIBO衍生物和Merck L-693，593的敏感性，表明Tyr 181和188对底物-酶相互作用至关重要。在持续存在奈韦拉平的情况下进行细胞培养选择导致出现对Cys具有耐药性的HIV-1，Tyr 181，这引起了临床需要联合药物治疗的担忧。
Nevirapine, a dipyridodiazepinone, is a highly specific inhibitor of HIV-1 reverse transcriptase (RT) which exhibits an IC50 = 84nM in enzyme assays and IC50 = 40nM against HIV-1 replication in cell culture. This nonnucleoside inhibitor acts noncompetitively with respect to nucleoside triphosphates, template and primer suggesting that nevirapine does not bind to the active site of RT. Studies employing an azido analogue of nevirapine as a photoaffinity probe indicated that one molecule of inhibitor is sufficient to inactivate one molecule of heterodimeric enzyme and demonstrated that only the p66 subunit of p66/p51 heterodimeric RT is covalently labeled by this probe. When subjected to tryptic mapping, Tyr 181 and Tyr 188 were labeled with probe and consequently these aromatic residues are apparently near or actually within the RT binding site for nevirapine. The extent to which Tyr 181 and Tyr 188 participate/contribute to nevirapine binding was determined by making amino acid substitutions at these positions using the corresponding residues from HIV-2 RT which is not sensitive to nevirapine. A change at either position dramatically decreased the enzymes' sensitivity to nevirapine, as well as to TIBO derivative and Merck L-693,593, indicating that both Tyr 181 and 188 are crucial for inhibitor-enzyme interaction. Cell culture selection in the continued presence of nevirapine results in the appearance of resistant HIV-1, Tyr 181 to Cys, raising the concern that combination drug therapy will be required in the clinic.