Shiga-like toxins are neutralized by tailored multivalent carbohydrate ligands
Shiga-like toxins are neutralized by tailored multivalent carbohydrate ligands
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DOI：
10.1038/35001095
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发表时间：
2000-02-10
期刊：
影响因子：
64.8
通讯作者：
Bundle, DR
中科院分区：
文献类型：
--
作者：
Kitov, PI;Sadowska, JM;Bundle, DR
由滋贺和霍乱毒素引起的疾病每年造成数百万人死亡（1）。两者都属于细菌AB（5）毒素的临床重要子集，由酶活性A亚基组成，在B-5同五聚体识别寡糖后进入易感哺乳动物细胞（2，3），治疗可能针对强制性寡糖-毒素识别事件（4），但碳水化合物-蛋白质相互作用的低固有亲和力阻碍了低分子量抑制剂的开发（5）。毒素通过同时结合五种或更多种细胞表面碳水化合物来规避低亲和力（6）。在此，我们证明了使用大肠杆菌O 157：H7志贺样毒素I（SLT-I）的B-5亚基的晶体结构与其碳水化合物受体的类似物复合（6）来设计具有亚纳摩尔抑制活性的寡价水溶性碳水化合物配体（命名为STARFISH）。体外抑制活性比单价配体高1- 1000万倍，是迄今为止报道的志贺样毒素I和II的任何抑制剂的最高摩尔活性。STARFISH/志贺样毒素I复合物的晶体学解释了这种活性。在五个间隔臂的每一个的尖端处的两个三糖受体同时接合两个毒素分子的所有五个B亚基。
The diseases caused by Shiga and cholera toxins account for the loss of millions of lives each year(1). Both belong to the clinically significant subset of bacterial AB(5) toxins consisting of an enzymatically active A subunit that gains entry to susceptible mammalian cells after oligosaccharide recognition by the B-5 homopentamer(2,3), Therapies might target the obligatory oligosaccharide-toxin recognition event(4), but the low intrinsic affinity of carbohydrate-protein interactions hampers the development of low-molecular-weight inhibitors(5). The toxins circumvent low affinity by binding simultaneously to five or more cell-surface carbohydrates(6), Here we demonstrate the use of the crystal structure of the B-5 subunit Of Escherichia coli O157:H7 Shiga-like toxin I (SLT-I) in complex with an analogue of its carbohydrate receptor(6) to design an oligovalent, water-soluble carbohydrate ligand (named STARFISH), with subnanomolar inhibitory activity. The in vitro inhibitory activity is 1-10-million-fold higher than that of univalent ligands and is by far the highest molar activity of any inhibitor yet reported for Shiga-like toxins I and II. Crystallography of the STARFISH/Shiga-like toxin I complex explains this activity. Two trisaccharide receptors at the tips of each of five spacer arms simultaneously engage all five B subunits of two toxin molecules.