Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In t...Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In this study,by structural modification of a retrograde transport blocker Retro-2cyc1,a series of novel compounds were obtained.The primary screen revealed that compound 27 has an improved antiricin activity compare to positive control.In vitro pre-exposure evaluation in Madin-Darby Canine Kidney(MDCK)cells demonstrated that 27 is a powerful anti-ricin compound with an EC50 of 41.05 nmol/L against one LC(lethal concentration,5.56 ng/mL)of ricin.Further studies surprisingly indicated that 27 confers post-exposure activity against ricin intoxication.An in vivo study showed that 1 h post-exposure administration of 27 can improve the survival rate as well as delay the death of ricin-intoxicated mice.A drug combination of 27 with monoclonal antibody mAb4 C13 rescued mice from one LD(lethal dose)ricin challenge and the survival rate of tested animals is 100%.These results represent,for the first time,indication that small molecule retrograde transport blocker confers both in vitro and in vivo post-exposure protection against ricin and therefore provides a promising candidate for the development of anti-ricin medicines.展开更多
目的运用计算机辅助蛋白质分子设计的方法设计针对蓖麻毒素A链（RTA）的拮抗肽，实现在大肠杆菌BL21中的可溶性表达，并对其生物学活性进行评价。方法根据RTA的晶体结构、RTA-rRNA相互作用复合物模型，在CVFF（consistent-valence force...目的运用计算机辅助蛋白质分子设计的方法设计针对蓖麻毒素A链（RTA）的拮抗肽，实现在大肠杆菌BL21中的可溶性表达，并对其生物学活性进行评价。方法根据RTA的晶体结构、RTA-rRNA相互作用复合物模型，在CVFF（consistent-valence force field）、Amber力场下，对RTA的空间构象进行理论模拟，初步确定其生物活性功能域；然后针对该功能域设计小分子拮抗肽，并借助人抗体重链可变区骨架，在CDR3区对拈抗肽进行展示，用重叠延伸PCR全基因合成人源化的单域抗体并克隆至载体pET-32a（＋）；双酶切和DNA测序技术对构建的载体进行鉴定；IPTG诱导人源化的单域抗体表达，用镍离子亲和层析纯化，竞争ELISA和MTr法分别进行结合和中和活性检测。结果从头搭建并设计合成了人源化的单域抗体，实现了其原核表达，并进行了生物活性检测；建立了基于人源化的单域抗体的RTA和蓖麻毒素检测方法。结论研究结果为新型蓖麻毒素小分子拈抗剂的研制奠定了理论和实验基础。展开更多
基金the financial supports of the National Science and Technology Major Projects for"Major New Drugs Innovation and Development"(2018ZX09711003-001-001)of China.
文摘Ricin is a highly toxic type 2 ribosome-inactivating protein(RIP)which is extracted from the seeds of castor beans.Ricin is considered a potential bioterror agent and no effective antidote for ricin exists so far.In this study,by structural modification of a retrograde transport blocker Retro-2cyc1,a series of novel compounds were obtained.The primary screen revealed that compound 27 has an improved antiricin activity compare to positive control.In vitro pre-exposure evaluation in Madin-Darby Canine Kidney(MDCK)cells demonstrated that 27 is a powerful anti-ricin compound with an EC50 of 41.05 nmol/L against one LC(lethal concentration,5.56 ng/mL)of ricin.Further studies surprisingly indicated that 27 confers post-exposure activity against ricin intoxication.An in vivo study showed that 1 h post-exposure administration of 27 can improve the survival rate as well as delay the death of ricin-intoxicated mice.A drug combination of 27 with monoclonal antibody mAb4 C13 rescued mice from one LD(lethal dose)ricin challenge and the survival rate of tested animals is 100%.These results represent,for the first time,indication that small molecule retrograde transport blocker confers both in vitro and in vivo post-exposure protection against ricin and therefore provides a promising candidate for the development of anti-ricin medicines.
文摘目的运用计算机辅助蛋白质分子设计的方法设计针对蓖麻毒素A链（RTA）的拮抗肽，实现在大肠杆菌BL21中的可溶性表达，并对其生物学活性进行评价。方法根据RTA的晶体结构、RTA-rRNA相互作用复合物模型，在CVFF（consistent-valence force field）、Amber力场下，对RTA的空间构象进行理论模拟，初步确定其生物活性功能域；然后针对该功能域设计小分子拮抗肽，并借助人抗体重链可变区骨架，在CDR3区对拈抗肽进行展示，用重叠延伸PCR全基因合成人源化的单域抗体并克隆至载体pET-32a（＋）；双酶切和DNA测序技术对构建的载体进行鉴定；IPTG诱导人源化的单域抗体表达，用镍离子亲和层析纯化，竞争ELISA和MTr法分别进行结合和中和活性检测。结果从头搭建并设计合成了人源化的单域抗体，实现了其原核表达，并进行了生物活性检测；建立了基于人源化的单域抗体的RTA和蓖麻毒素检测方法。结论研究结果为新型蓖麻毒素小分子拈抗剂的研制奠定了理论和实验基础。
