Protective Antigen Domain 4
Protective antigen (PA) is the central component of the three-part protein toxin secreted by Bacillus anthracis, the organism responsible for anthrax. Homologues of PA have been found in several spore-forming Gram-positive bacteria, and share the ability to translocate toxic enzymes into the host cytosol.The PA monomer is organised mainly into antiparallel beta-sheets and has four domains: an N-terminal domain (domain 1) containing two calcium ions and the cleavage site for activating proteases; a heptamerisation domain (domain 2) containing a large flexible loop implicated in membrane insertion; a small domain of unknown function (domain 3); and a carboxy-terminal receptor-binding domain (domain 4) [PMID: 9039918].
This entry represents domain 4 of PA, which has an immunoglobulin-like fold. Domain 4 plays a key role in cellular receptor recognition, as well as in pH-dependent pore formation[PMID: 19722284].
Sequence and Features
- 10Illegal SpeI site found at 361
- 12Illegal SpeI site found at 361
- 21COMPATIBLE WITH RFC
- 23Illegal SpeI site found at 361
- 25Illegal SpeI site found at 361
- 1000Illegal SpeI site found at 361