天花粉蛋白抗人艾滋病毒构效关系的研究

天花粉蛋白是我国自行创制为数不多的创新药物。它具有显著的体内体外抗艾滋病病毒作用。变态反应和神经毒作用限制了其应用。本项目旨利用基因工程定点突变技术研究天花粉蛋白结构与抗HIV活性之间的关系及作用机制，寻找有显著抗HIV活性而毒付作用低的天花粉蛋白突变体，拓宽其临床应用适应症，为新药的创制奠定基础。

Trichosanthin (TCS) is a type I ribosome-inactivating protein (RIP) isolated from the root tubers of the Chinese medicinal herb Trichosanthes kirilowii Maxim (cucurbitaceae). It possessed anti-HIV activity in vivo and in vitro. Unfortunately, the side effects of TCS hindered its further clinically usage. The researchers hope to change or modify TCS molecule, and to achieve the results that mutated TCS decreased its neurotoxicity side effect and subsequent abnormal reaction. It is essential to explore the relationship between TCS structure and its functions. . By site-directed mutagenesis, 17 TCS mutants of RIP active sites, C-terminus, antigen determinat sites and PEG20k couping were constructed. The anti-HIV-1 activity of all the mutants were assayed. The results showed that the RIP activity contributed mainly to its anti-HIV-1 activity but not the only factor. The 2 C-terminal mutants added signal peptide decreased anti-HIV-1 activity significantly while holding most of the RIP activity. Anti-HIV-1 activityof TCS may related to MAPK signaling. The results also showed that TCS antigen determinat sites mutation did not impair its anti-HIV-1 activity but PEG20k coupling. The mechanism of TCS anti-HIV-1 was primarily studied, the results indicated that TCS did not act on HIV-1reverse transcriptase and gp41.