Anthrax Protective Antigen, Bacillus anthracis, Nicked, Recombinant, B. anthracis

Recombinant, Bacillus anthracis anthrax protective antigen (nicked) expressed in a specialized strain of B. anthracis. PA₆₃ is the carboxyl-terminal 63-kDa fragment obtained by the proteolytic cleavage of the receptor-bound protective antigen (PA), one of the three proteins that comprise anthrax toxin. Unlike native PA, PA₆₃ oligomerizes to form a ring-shaped heptamer that binds up to three copies of EF and/or LF competitively and with high affinity (K_d ~1 nM). Whereas native PA persists on the cell surface, the heptamer is endocytosed, presumably because oligomerization aggregates anthrax toxin receptor. The endocytosed toxic complexes are trafficked to endosomal compartments where the low pH causes the PA63 heptamer to insert into the membrane and form a water-filled channel.

Cell permeable: no

Primary Target
EF and/or LF

Product does not compete with ATP.

Reversible: no

Lyophilized from 100 mM NaCL, 10 mM BIS-Tris propane, 1.25% trehalose, pH 8.5.

Following reconstitution aliquot and freeze (-20°C or- 70°C) for long term storage or refrigerate (4°C) for short-term (few hours) storage. Avoid rapid freeze-thaw cycles of solutions. Stock solutions are stable for up to 3 months at -20°C or -70°C.

Reconstitute in sterile 50% glycerol or sterile, distilled H₂O to a final concentration of 1 mg/ml. Addition of BSA to a concentration of 1 mg/ml may enhance stability.

Single major band at 63 kD by SDS-PAGE

Mogridge, J., et al. 2002. Proc. Natl. Acad. Sci. USA99, 7045.
Nassi, S., et al. 2002. Biochemistry41, 1445.
Singh, Y., et al. 1999. Infect. Immun.67, 1853.
Leppla, S.H. 1988. Methods Enzymol.165, 103.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)