NR-28544炭疽致死因子(LF-A),天然序列,重组炭疽杆菌(毒素）
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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