Preliminary studies of C. botulinum progeniotr toxin B

描述（由申请人提供）：肉毒杆菌神经毒素是由肉毒杆菌释放的一种称为祖毒素的蛋白质复合物，引起肉毒中毒，如果不立即和适当治疗，其死亡率很高，因此引起相当大的关注。它也是潜在的生物战威胁。它在生物恐怖主义中的潜在用途使得必须制定措施来保护武装部队和一般公众。这项建议的总目标是协助制订和设计这些措施，即药品和疫苗。长期目标是通过x射线晶体学确定原毒素B的三维结构，了解由神经毒素和其他相关蛋白质形成的肉毒杆菌原毒素复合物组分组装的功能和目的。人们认为，祖毒素保护肉毒杆菌神经毒素免受胃肠道中存在的低pH和肽酶的恶劣条件。了解这些蛋白质的三维结构以及它们与神经毒素的相互作用将有助于理解它们保护神经毒素的机制。祖毒素能够被肠道吸收，降解程度最低，因此通过对毒素分子进行适当修饰，使其成为口服药物载体的合适候选者。此外，它将有助于设计除肉毒杆菌和破伤风以外的许多疾病的口服疫苗。当包括动物和鸟类在内的大量人口要接种疫苗时，这一点尤为重要。短期目标是使M和L形式的祖毒素B结晶，用于x射线衍射分析，并在获得晶体后开始进行结构分析。下面列出了导致总体目标的个人具体目标。1. 目的：对肉毒杆菌原毒素B进行M型和L型结晶，用x射线晶体学测定其三维结构。2. 利用布鲁克海文国家实验室的STEM设施测量祖细胞复合体的质量。从B祖毒素M型和L型的晶体中获得初步的晶体数据。

DESCRIPTION (provided by applicant): Botutinum neurotoxin, released as a protein complex called progenitor toxin by the bacterium Clostridium botulinum, causes the disease botulism that is of considerable concern because of its high mortality rate when not treated immediately and properly. It is also a potential biowarfare threat. Its potential use in bioterrorism makes it imperative to develop measures to protect the armed forces and the public in general. The overall objective of this proposal is to aid in developing and designing such measures viz., medicines and vaccines. The long-range goal is to achieve this by understanding the function and purpose of the assembly of the components of C. botutinum progenitor toxins, complex formed by neurotoxin and other associated proteins, by determining the three-dimensional structure of progenitor toxin B via X-ray crystallography. It is believed that progenitor toxins protect the botulinum neurotoxin from the harsh conditions of low pH and peptidases present in the gastrointestinal tract. Knowledge of the three-dimensional organization of these proteins and their interactions with the neurotoxin and one another will lead to the understanding of the mechanism by which they protect the neurotoxin. Progenitor toxin's ability to be absorbed from the gut with minimum degradation makes it a suitable candidate for use as a carrier of oral medicines by appropriate modification of the toxin molecule. Additionally, it will help in designing oral vaccines for many afflictions besides botulism and tetanus. This is particularly important when a large population including animals and birds is to be vaccinated. The short-range goals are to crystallize M and L forms of progenitor toxin B for X-ray diffraction analysis and initiate structural analysis when crystals are obtained. The individual specific aims leading to the overall goal are listed below. 1. To crystallize M and L forms of C. botulinum progenitor toxin B for three-dimensional structure determination via X-ray crystallography. 2. To measure the mass of the progenitor complex with the use of the STEM facility at Brookhaven National Laboratory. 3. To obtain preliminary crystal data from the crystals of M and L forms of progenitor toxin B.