Sequence homology and structural analysis of the clostridial neurotoxins
Sequence homology and structural analysis of the clostridial neurotoxins
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DOI：
10.1006/jmbi.1999.2945
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发表时间：
1999-09-03
影响因子：
5.6
通讯作者：
Stevens, RC
中科院分区：
文献类型：
--
作者：
Lacy, DB;Stevens, RC
梭菌神经毒素（CNT）由破伤风神经毒素（TeNT）和肉毒杆菌神经毒素的七种血清型（BoNT A-G）组成，其特异性结合神经元细胞并通过切割参与突触囊泡膜融合的蛋白质来破坏神经递质释放。在本研究中，在1277个残基BoNT/A晶体结构的背景下分析了多个CNT序列，以深入了解毒性所需的结合、孔形成、易位和催化事件。的TeNT结合结构域的结构的BoNT/A的比较揭示了它们的表面性质的显着差异。此外，BoNT/A结合结构域C末端的关键色氨酸的溶剂可及性细化了神经节苷脂结合位点的位置。本研究包括从BoNT/A的单个冷冻晶体收集的数据，揭示了先前未观察到的易位结构域环的结合结构域方向和密度的轻微差异。这个循环和保守的带电残基与推定的孔形成序列的结构接近，使我们深入了解孔形成和易位的CNT机制。催化结构域的序列分析显示，附近的活性位点可能占碳纳米管之间的特异性差异的区域。它还揭示了一个三级结构，在一级序列中高度保守，这似乎对催化至关重要，但距离活性位点锌离子30埃。这一观察结果，沿着与分析的54个残基"带"从易位域进行了讨论方面的催化机制。(C)北京：科学出版社.
The clostridial neurotoxins (CNTs), comprised of tetanus neurotoxin (TeNT) and the seven serotypes of botulinum neurotoxin (BoNT A-G), specifically bind to neuronal cells and disrupt neurotransmitter release by cleaving proteins involved in synaptic vesicle membrane fusion. Ln this study, multiple CNT sequences were analyzed within the context of the 1277 residue BoNT/A crystal structure to gain insight into the events of binding, pore formation, translocation, and catalysis that are required for toxicity. A comparison of the TeNT-binding domain structure to that of BoNT/A reveals striking differences in their surface properties. Further, the solvent accessibility of a key tryptophan in the C terminus of the BoNT/A-binding domain refines the location of the ganglioside-binding site. Data collected from a single frozen crystal of BoNT/A are included in this study, revealing slight differences in the binding domain orientation as well as density for a previously unobserved translocation domain loop. This loop and the conservation of charged residues with structural proximity to putative pore-forming sequences lend insight into the CNT mechanism of pore formation and translocation. The sequence analysis of the catalytic domain revealed an area near the active-site likely to account for specificity differences between the CNTs. It revealed also a tertiary structure, highly conserved in primary sequence, which seems critical to catalysis but is 30 Angstrom from the active-site zinc ion. This observation, along with an analysis of the 54 residue "belt" from the translocation domain are discussed with respect to the mechanism of catalysis. (C) 1999 Academic Press.