Zhang Kai, Rathod Pradipsinh K
Department of Biology, The Catholic University of America, Washington, DC 20064, USA.
Science. 2002 Apr 19;296(5567):545-7. doi: 10.1126/science.1068274.
For half a century, successful antifolate therapy against Plasmodium falciparum malaria has been attributed to host-parasite differences in drug binding to dihydrofolate reductase-thymidylate synthase (DHFR-TS). Selectivity may also arise through previously unappreciated differences in regulation of this drug target. The DHFR-TS of Plasmodium binds its cognate messenger RNA (mRNA) and inhibits its own translation. However, unlike translational regulation of DHFR or TS in humans, DHFR-TS mRNA binding is not coupled to enzyme active sites. Thus, antifolate treatment does not relieve translational inhibition and parasites cannot replenish dead enzyme.
半个世纪以来,针对恶性疟原虫疟疾的成功抗叶酸治疗一直归因于宿主与寄生虫在药物与二氢叶酸还原酶 - 胸苷酸合成酶(DHFR - TS)结合方面的差异。选择性也可能源于此前未被重视的该药物靶点调控差异。疟原虫的DHFR - TS与其同源信使核糖核酸(mRNA)结合并抑制自身翻译。然而,与人类中DHFR或TS的翻译调控不同,DHFR - TS mRNA结合并不与酶活性位点偶联。因此,抗叶酸治疗不能解除翻译抑制,寄生虫无法补充死亡的酶。