Cidofovir and (S)-9-[3-hydroxy-(2-phosphonomethoxy)propyl]adenine are highly effective inhibitors of vaccinia virus DNA polymerase when incorporated into the template strand
Cidofovir and (S)-9-[3-hydroxy-(2-phosphonomethoxy)propyl]adenine are highly effective inhibitors of vaccinia virus DNA polymerase when incorporated into the template strand
复制标题
DOI：
10.1128/aac.01172-07
复制
发表时间：
2008-02-01
影响因子：
4.9
通讯作者：
Evans, David H.
中科院分区：
文献类型：
--
作者：
Magee, Wendy C.;Aldern, Kathy A.;Evans, David H.
无环核苷膦酸酯药物（S）-9- [3-羟基-（2-膦酰甲氧基）丙基]腺嘌呤[（S）HPMPA]是一种广谱抗病毒和抗寄生虫药物。先前的研究表明，该化合物的活性细胞内代谢产物（S）-HPMPA二磷酸[（S）-HPMPAp]是dATP的类似物，靶向DNA聚合酶。然而，（S）-HPMPA抑制DNA聚合酶的机制仍然难以捉摸。使用牛痘病毒作为模型系统，我们先前已经表明，西多福韦二磷酸（CDVpp），dCTP的类似物和相关的抗病毒剂，是牛痘病毒DNA聚合酶的不良底物，并起到抑制引物延伸和阻断3 '-至-5'校对核酸外切酶活性的作用。基于（S）-HPMPA的结构相似性和更大的抗病毒功效，我们预测（S）-HPMPAp将对牛痘聚合酶具有相似但比CDVpp更显著的作用。有趣的是，我们发现（S）-HPMPApp是病毒酶的良好底物，表现出与dATP相当的K-m和V-max参数，并且肯定不像CDVpp那样作为功能性链终止剂。代谢实验表明，（S）-HPMPA转化为（S）-HPMAPP，以a.比CDV转化为CDVpp的程度大得多，尽管两种药物在其50%有效浓度下对病毒DNA复制产生相同的作用。随后的研究表明，这两种化合物都可以忠实地掺入DNA中，但当CDV和（S）-HPMPA掺入模板链时，两者都强烈抑制跨病变DNA合成。因此，核苷膦酸盐药物对DNA聚合酶表现出至少两种不同的作用，这取决于酶以何种形式遇到药物。
The acyclic nucleoside phosphonate drug (S)-9- [3-hydroxy-(2-phosphonomethoxy)propyl] adenine [(S)HPMPA], is a broad-spectrum antiviral and antiparasitic agent. Previous work has shown that the active intracellular metabolite of this compound, (S)-HPMPA diphosphate [(S)-HPMPApp], is an analog of dATP and targets DNA polymerases. However, the mechanism by which (S)-HPMPA inhibits DNA polymerases remains elusive. Using vaccinia virus as a model system, we have previously shown that cidofovir diphosphate (CDVpp), an analog of dCTP and a related antiviral agent, is a poor substrate for the vaccinia virus DNA polymerase and acts to inhibit primer extension and block 3'-to-5' proofreading exonuclease activity. Based on structural similarities and the greater antiviral efficacy of (S)-HPMPA, we predicted that (S)-HPMPApp would have a similar, but more pronounced effect on vaccinia polymerase than CDVpp. Interestingly, we found that (S)-HPMPApp is a good substrate for the viral enzyme, exhibiting K-m and V-max parameters comparable to those of dATP, and certainly not behaving like CDVpp as a functional chain terminator. Metabolic experiments indicated that (S)-HPMPA is converted to (S)-HPMPApp to a. much greater extent than CDV is converted to CDVpp, although both drugs cause identical effects on virus DNA replication at their 50% effective concentration. Subsequent studies showed that both compounds can be faithfully incorporated into DNA, but when CDV and (S)-HPMPA are incorporated into the template strand, both strongly inhibit trans-lesion DNA synthesis. It thus appears that nucleoside phosphonate drugs exhibit at least two different effects on DNA polymerases depending upon in what form the enzyme encounters the drug.