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Recombinant anthrax lethal factor (LF, 90 kDa) containing the native alanine (A) at the N-terminus was produced using a plasmid licensed from the NIH. The lethal factor produced from this plasmid has been designated LF-A by the manufacturer. The plasmid was introduced into a non-sporulating, avirulent strain of Bacillus anthracis lacking both of the wild type plasmids, pX01 and pX02. Recombinant LF-A was purified using conventional chromatographic techniques. The resulting purified protein lacks all other anthrax virulence factors.
A recombinant form of the LF protein containing
two additional amino acids at the N-terminus, a histidine (H) and a methionine
(M), beyond the native N-terminal alanine (A), has been or is currently
available from BEI Resources (NR-142, NR-404, NR-570, NR-723, NR-724, NR-2673,
NR-4367, NR-4368). This form of the protein has been recently designated
LF-HMA by the manufacturer and is also produced in Bacillus anthracis. Note: LF-A has been reported to have 3-fold higher
potency than LF-HMA in cell culture cytotoxicity assays and in rat lethality
studies.
LF is a zinc-dependent metalloprotease which
cleaves the amino terminus of signaling proteins of the mitogen-activated
protein kinase family (MAPKK), destroying their ability to signal. In
vivo, recombinant LF binds to a cleaved form of recombinant protective
antigen (PA), and is transported by PA into the cytosol of the macrophage where
LF exerts its pathogenic effect.
Each
vial contains approximately 0.1 mg (lyophilized) of recombinant LF-A from Bacillus
anthracis.
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BEI Resources 自 2003 年起由美国典型培养物保藏中心 (ATCC) 根据合同管理。2016 年 5 月， ATCC获得了一份为期七年的继续管理 BEI Resources的合同。合同范围已扩大到更全面的研究目录材料，包括由其他政府支持的研究项目存放的材料，将提供给生物防御和新兴传染病科学界。真菌、寄生虫、载体和其他相关材料已添加到现有的细菌、病毒和毒素试剂中，涵盖 NIAID A、B 和 C 类优先病原体和 NIAID 指定的新发传染病病原体和生物。
