Lacy, D. BordenWigelsworth, Darran J.Melnyk, Roman A.Harrison, Stephen C.Collier, R. John2019-10-132004Lacy, D. B., D. J. Wigelsworth, R. A. Melnyk, S. C. Harrison, and R. J. Collier. 2004. “Structure of Heptameric Protective Antigen Bound to an Anthrax Toxin Receptor: A Role for Receptor in PH-Dependent Pore Formation.” Proceedings of the National Academy of Sciences 101 (36): 13147–51. doi:10.1073/pnas.0405405101.0027-84240744-28311091-6490http://nrs.harvard.edu/urn-3:HUL.InstRepos:41542817After binding to cellular receptors and proteolytic activation, the protective antigen component of anthrax toxin forms a heptameric prepore. The prepore later undergoes pH-dependent conversion to a pore, mediating translocation of the edema and lethal factors to the cytosol. We describe structures of the prepore (3.6 Angstrom) and a p repo re: receptor complex (4.3 Angstrom) that reveal the location of pore-forming loops and an unexpected interaction of the receptor with the pore-forming domain. Lower pH is required for prepore-to-pore conversion in the presence of the receptor, indicating that this interaction regulates pH-dependent pore formation. We present an example of a receptor negatively regulating pH-dependent membrane insertion.en-USJournal Article2019-10-1310.1073/pnas.0405405101