The biological activity of botulinum neurotoxin type C is dependent upon novel types of ganglioside binding sites
The biological activity of botulinum neurotoxin type C is dependent upon novel types of ganglioside binding sites
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DOI：
10.1111/j.1365-2958.2011.07682.x
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发表时间：
2011-07-01
影响因子：
3.6
通讯作者：
Binz, Thomas
中科院分区：
文献类型：
--
作者：
Strotmeier, Jasmin;Gu, Shenyan;Binz, Thomas
七种肉毒杆菌神经毒素(BONT)通过选择性地切割水泡融合机械的核心组件而导致肌肉瘫痪。它们的非凡活动主要依赖于进入神经元的高度特异性。有关BoNT/A、B、E、F和G的数据表明，Entry通过已建立的神经节苷脂结合区和突触小泡蛋白与复杂的神经节苷脂发生双重受体相互作用。在这里，我们报道了单独的BONT/C细胞结合片段以及与唾液酸复合的高分辨晶体结构。已建立的神经节苷脂结合区的WY基序特征位于一个暴露的环上。唾液酸分别配位在BONT/B和G中突触素结合口袋附近的新位置和BONT/D和TANT中的唾液酸结合部位。利用突触体和固定化神经节苷脂与BoNT/C突变体的结合研究表明，神经节苷脂结合WY环、新发现的唾液酸配位口袋以及与其他BoNTs建立的神经节苷脂结合区对应的区域参与了神经节苷脂的相互作用。利用神经节苷脂缺陷小鼠进行的膈神经横隔膜活性测试进一步证明，BONT/C的生物活性依赖于至少两个结合部位的神经节苷脂相互作用。这些数据表明，在梭状芽胞杆菌神经毒素中，BONT/C具有独特的细胞结合和进入机制。
The seven botulinum neurotoxins (BoNT) cause muscle paralysis by selectively cleaving core components of the vesicular fusion machinery. Their extraordinary activity primarily relies on highly specific entry into neurons. Data on BoNT/A, B, E, F and G suggest that entry follows a dual receptor interaction with complex gangliosides via an established ganglioside binding region and a synaptic vesicle protein. Here, we report high resolution crystal structures of the BoNT/C cell binding fragment alone and in complex with sialic acid. The WY-motif characteristic of the established ganglioside binding region was located on an exposed loop. Sialic acid was co-ordinated at a novel position neighbouring the binding pocket for synaptotagmin in BoNT/B and G and the sialic acid binding site in BoNT/D and TeNT respectively. Employing synaptosomes and immobilized gangliosides binding studies with BoNT/C mutants showed that the ganglioside binding WY-loop, the newly identified sialic acid-co-ordinating pocket and the area corresponding to the established ganglioside binding region of other BoNTs are involved in ganglioside interaction. Phrenic nerve hemidiaphragm activity tests employing ganglioside deficient mice furthermore evidenced that the biological activity of BoNT/C depends on ganglioside interaction with at least two binding sites. These data suggest a unique cell binding and entry mechanism for BoNT/C among clostridial neurotoxins.