6UJI

Low resolution crystal structure (5.5 A) of the anthrax toxin protective antigen heptamer prepore D425A mutant

Summary for 6UJI

• Entry DOI: 10.2210/pdb6uji/pdb
• Descriptor: Protective antigen PA-63 (1 entity in total)
• Functional Keywords: anthrax toxin, pa63 heptamer, toxin
• Biological source: Bacillus anthracis
• Total number of polymer chains: 14
• Total formula weight: 888657.00

Authors

Lovell, S.,Mehzabeen, N.,Battaile, K.P.,Bann, J.G. (deposition date: 2019-10-03, release date: 2020-10-07, Last modification date: 2023-10-11)

Primary citation

Scott, H.,Huang, W.,Andra, K.,Mamillapalli, S.,Gonti, S.,Day, A.,Zhang, K.,Mehzabeen, N.,Battaile, K.P.,Raju, A.,Lovell, S.,Bann, J.G.,Taylor, D.J.
Structure of the anthrax protective antigen D425A dominant negative mutant reveals a stalled intermediate state of pore maturation.
J.Mol.Biol., :167548-167548, 2022

PubMed Abstract: The tripartite protein complex produced by anthrax bacteria (Bacillus anthracis) is a member of the AB family of β-barrel pore-forming toxins. The protective antigen (PA) component forms an oligomeric prepore that assembles on the host cell surface and serves as a scaffold for binding of lethal and edema factors. Following endocytosis, the acidic environment of the late endosome triggers a pH-induced conformational rearrangement to promote maturation of the PA prepore to a functional, membrane spanning pore that facilitates delivery of lethal and edema factors to the cytosol of the infected host. Here, we show that the dominant-negative D425A mutant of PA stalls anthrax pore maturation in an intermediate state at acidic pH. Our 2.7 Å cryo-EM structure of the intermediate state reveals structural rearrangements that involve constriction of the oligomeric pore combined with an intramolecular dissociation of the pore-forming module. In addition to defining the early stages of anthrax pore maturation, the structure identifies asymmetric conformational changes in the oligomeric pore that are influenced by the precise configuration of adjacent protomers.

PubMed: 35304125
DOI: 10.1016/j.jmb.2022.167548

Experimental method

X-RAY DIFFRACTION (5.5 Å)