X-RAY CRYSTAL STRUCTURE OF CLOSTRIDIUM PERFRINGENS BETA 2 TOXIN

点击翻译按钮获取中文摘要

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Beta 2 toxin is a 28kD exotoxin produced by Clostridium Perfringens. It is implicated in necrotic enteritis in man and animals, a disease that is characterized by a sudden acute onset with lethal hemorrhagic mucosal ulceration. It is associated with beef contamination resulting in food poisoning in humans. It is pore forming in host cell membranes leaking essential ions leading to cytotoxicity. Pore forming toxins typically transform from soluble monomeric proteins to oligomers that form transmembrane channels. The membrane insertion segment could be alpha helical or part of a beta sheet. Recent structural studies provide some insight into the conformational changes associated with such proteins on membrane association. Our goal is to understand the function of beta 2 toxin from a structural perspective and identify key residues that aid in membrane binding, antigenicity and pore formation. Ultimately we would like to develop a dairy vaccine from the insight gained from solving the 3-dimensional structure. We have grown crystals of beta 2 toxin from Clostridium Perfringens using LiSO4 and Peg3350 as precipitant. We have worked out the best cryo conditions with these crystals. Screening at our local X-ray source has shown some diffraction upto 4 Angstroms. We would like to a. Collect a native data set b. Try quick halide soaks and collect MAD data in order to solve the structure using MAD techniques