Relationship between antiviral activity and host toxicity:: Comparison of the incorporation efficiencies of 2′,3′-dideoxy-5-fluoro-3′-thiacytidine-triphosphate analogs by human immunodeficiency virus type 1 reverse transcriptase and human mitochondrial DNA polymerase
Relationship between antiviral activity and host toxicity:: Comparison of the incorporation efficiencies of 2′,3′-dideoxy-5-fluoro-3′-thiacytidine-triphosphate analogs by human immunodeficiency virus type 1 reverse transcriptase and human mitochondrial DNA polymerase
复制标题
DOI：
10.1128/aac.48.4.1300-1306.2004
复制
发表时间：
2004-04-01
影响因子：
4.9
通讯作者：
Anderson, KS
中科院分区：
文献类型：
--
作者：
Feng, JY;Murakami, E;Anderson, KS
恩曲他滨[(-)FTC；(-)-beta-L-2‘-3’-dideoxy-5-fluoro-3‘-thiacytidine]是美国食品和药物管理局最近批准的一种用于治疗人类免疫缺陷病毒的恶硫环核苷类似物。在结构上，(-)FTC与拉米夫定[(-)3TC]非常相似，只是前者在胞嘧啶环上是5-氟化的。在HIV-1逆转录酶(RT)酶分析中，(-)FTC[(-)FTC-TP]的三磷酸被同时掺入DNA-DNA和DNA-RNA引物模板，效率分别是(-)3TC-TP的近3倍和10倍。动物研究和临床试验研究表明，(-)FTC具有良好的安全性。然而，为了全面了解抑制和毒性的分子机制，需要详细研究与核苷毒性相关的宿主酶-人线粒体DNA聚合酶伽马对(-)FTC-TP的掺入。在稳态前动力学分析中，我们研究了通过重组人线粒体DNA聚合酶将(-)FTC-TP及其对映体(+)FTC-TP掺入DNA-DNA引物模板。(-)FTC-TP的掺入效率分别比dCTP、ddCTP、(+)3TC-TP、(+)FTC-TP和(-)3TC-TP低2.9×10(5)-1.1×10(5)-1.6×10(3)-、7.9×10(3)-和100倍。聚合酶γ的3‘-5’外切酶活性从相应的链末端24聚体DNA中去除(-)FTC-MP的速度等于去除(+)FTC-MP的速率，比去除(-)3TC-MP和(+)3TC-MP慢2倍，比切除dCMP慢4.6倍。这些结果表明，HIV-1RT和聚合酶伽马在底物结构的偏好方面存在明显的差异。
Emtricitabine [(-)FTC; (-)-beta-L-2'-3'-dideoxy-5-fluoro-3'-thiacytidine] is an oxathiolane nucleoside analog recently approved by the Food and Drug Administration for the treatment of human immunodeficiency virus (HIV). Structurally, (-)FTC closely resembles lamivudine [(-)3TC] except that the former is 5-fluorinated on the cytosine ring. In HIV-1 reverse transcriptase (RT) enzymatic assays, the triphosphate of (-)FTC [(-)FTC-TP] was incorporated into both DNA-DNA and DNA-RNA primer-templates nearly 3- and 10-fold more efficiently than (-)3TC-TP. Animal studies and clinical trial studies have demonstrated a favorable safety profile for (-)FTC. However, a detailed study of the incorporation of (-)FTC-TP by human mitochondrial DNA polymerase gamma, a host enzyme associated with nucleoside toxicity, is required for complete understanding of the molecular mechanisms of inhibition and toxicity. We studied the incorporation of (-)FTC-TP and its enantiomer (+)FTC-TP into a DNA-DNA primer-template by recombinant human mitochondrial DNA polymerase in a pre-steady-state kinetic analysis. (-)FTC-TP was incorporated 2.9 x 10(5)- 1.1 x 10(5)- 1.6 x 10(3)-, 7.9 x 10(3)-, and 100-fold less efficiently than dCTP, ddCTP, (+)3TC-TP, (+)FTC-TP, and (-)3TC-TP, respectively. The rate of removal of (-)FTC-MP from the corresponding chain-terminated 24-mer DNA by polymerase gamma's 3'-->5' exonuclease activity was equal to the removal of (+)FTC-MP, 2-fold slower than the removal of (-)3TC-MP and (+)3TC-MP, and 4.6-fold slower than the excision of dCMP. These results demonstrate that there are clear differences between HIV-1 RT and polymerase gamma in terms of preferences for substrate structure.