Anthrax Lethal Factor: Difference between revisions

Lethal Factor (LF) is one of the enzymatic components belonging to the [http://en.wikipedia.org/wiki/Anthrax_toxin Anthrax Toxin]. Anthrax toxin is a three protein exotoxin secreted by the bacterium [http://en.wikipedia.org/wiki/Bacillus_anthracis ''Bacillus Anthracis''] made up of a binding protein known as the protective antigen (PA) and two enzyme components known as edema factor (EF) and lethal factor (LF). <ref name=Collier>PMID: 14570563</ref>

Anthrax Toxin, encoded by plasmid pXO2, is considered an AB toxin, with two A domains (EF and LF) and one B domain (PA). <ref name=Collier>PMID: 14570563</ref> <ref>Brenda A. Wilson, Abigail A. Salyers, Dixie D. Whitt, and Malcolm E. Winkler. Third Edition. Bacterial Pathogenesis A Molecular Approach</ref> On their own, these three domains are nontoxic, but any combination involving PA with EF and/or LF is what causes the physiological effects. <ref>Kenneth Todar, PhD. (2008). http://textbookofbacteriology.net/Anthrax_3.html</ref> Initially PA is a 83kDa protein which binds to the host Anthrax toxin Receptor (ATR). Upon binding, PA is cleaved into two fragments by a furin proteases to become a 63 kDa protein bound to the ATR. Cleavage of PA allows self associate to occur which forms a ring shaped heptamer know as the pore precursor (prepore). The prepore is now able to bind up to three molecules of EF and/or LF, leading to endocytosis of the complex. In the endosome, the prepore converts to a transmembrane pore, allowing translocation of EF and LF to the cytosol through a mechanism that is not will understood. EF and LF are now able to carry out their enzymatic activity on the host cell. <ref name=Collier>PMID: 14570563</ref>