Dinitroaniline Activity in Toxoplasma gondii Expressing Wild-Type or Mutant α-Tubulin
Dinitroaniline Activity in Toxoplasma gondii Expressing Wild-Type or Mutant α-Tubulin
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DOI：
10.1128/aac.01150-09
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发表时间：
2010-04-01
影响因子：
4.9
通讯作者：
Morrissette, Naomi
中科院分区：
文献类型：
--
作者：
Ma, Christopher;Tran, Johnson;Morrissette, Naomi
人类寄生虫弓形虫对二硝基苯胺化合物敏感，二硝基苯胺化合物选择性地破坏各种原生动物中的微管，但对脊椎动物宿主细胞微管或其他功能没有可检测的影响。野生型T. 0.5 - 2.5 μ M的安磺灵可抑制弓形虫，但在预测的二硝基苯胺结合位点中具有氨基酸取代的突变寄生虫赋予高达40 μ M的安磺灵抗性。然而，二硝基苯胺和α-微管蛋白中的结合位点之间的精确相互作用仍不清楚。我们已经调查了12二硝基苯胺和相关化合物amiprophos甲基野生型和二硝基苯胺抗性寄生虫线，含有拟议的结合位点突变的活动。这些数据表明，二硝胺是最有效的二硝基苯胺，以抑制野生型寄生虫和大多数耐药株系的弓形虫生长。二硝胺在Meta位上具有胺基，该胺基不存在于本文测试的任何其他二硝基苯胺中，根据对接数据预测该胺基与残基Arg 2和Gln 133形成氢键。值得注意的是，虽然结合位点突变Ile 235 Val赋予对大多数二硝基苯胺的抗性增加，但它赋予对GB-II-5的敏感性增加，GB-II-5是一种针对动质体微管蛋白活性优化的化合物。动质体寄生虫在α-微管蛋白的235位具有缬氨酸，而顶复体寄生虫在该位点具有异亮氨酸。我们认为，这种异质性的结合位点的环境影响相对二硝基苯胺的敏感性在不同的原生动物谱系，并假设一个突变，使apicomplexan二硝基苯胺结合位点更像动质体网站增加敏感性的二硝基苯胺优化后的寄生虫的活动。
The human parasite Toxoplasma gondii is sensitive to dinitroaniline compounds which selectively disrupt microtubules in diverse protozoa but which have no detectable effect on vertebrate host cell microtubules or other functions. Replication of wild-type T. gondii is inhibited by 0.5 to 2.5 mu M oryzalin, but mutant parasites harboring amino acid substitutions in the predicted dinitroaniline binding site confer resistance up to 40 mu M oryzalin. However, the precise interaction between dinitroanilines and the binding site in alpha-tubulin remains unclear. We have investigated the activity of 12 dinitroanilines and the related compound amiprophos methyl on wild-type and dinitroaniline-resistant parasite lines that contain proposed binding site mutations. These data indicate that dinitramine is the most effective dinitroaniline to inhibit Toxoplasma growth in wild-type parasites and most resistant lines. Dinitramine has an amine group at the meta position not present in any of the other dinitroanilines tested here that is predicted to form hydrogen bonds with residues Arg2 and Gln133 according to docking data. Remarkably, although the binding site mutation Ile235Val confers increased resistance to most dinitroanilines, it confers increased sensitivity to GB-II-5, a compound optimized for activity against kinetoplastid tubulin. Kinetoplastid parasites have a valine at position 235 of alpha-tubulin, whereas apicomplexan parasites have an isoleucine at this site. We suggest that this heterogeneity in binding site environment influences relative dinitroaniline sensitivity in distinct protozoan lineages and hypothesize that a mutation that makes the apicomplexan dinitroaniline binding site more like the kinetoplastid site increases sensitivity to a dinitroaniline optimized for activity in the latter parasites.