Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 9-mer - A7B2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: assay for oligomerization

Macromolecule Content

• Total Structure Weight: 757.85 kDa 
• Atom Count: 42822 
• Residue Count: 5374 
• Unique protein chains: 2

6UZD

Anthrax toxin protective antigen channels bound to edema factor

• DOI: 10.2210/pdb6UZD/pdb
• EMDataResource: EMD-20957

• Classification: TRANSLOCASE
• Organism(s): Bacillus anthracis
• Expression System: Escherichia coli 'BL21-Gold(DE3)pLysS AG
• Mutation(s): No 


• Deposited: 2019-11-14 Released: 2020-03-04 
• Deposition Author(s): Hardenbrook, N.J., Liu, S., Zhou, K., Zhou, Z.H., Krantz, B.A.
• Funding Organization(s): National Science Foundation (NSF, United States), National Institutes of Health/National Center for Research Resources (NIH/NCRR)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.40 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Atomic structures of anthrax toxin protective antigen channels bound to partially unfolded lethal and edema factors.

Hardenbrook, N.J., Liu, S., Zhou, K., Ghosal, K., Hong Zhou, Z., Krantz, B.A.

(2020) Nat Commun 11: 840-840

• PubMed: 32047164 
• DOI: 10.1038/s41467-020-14658-6
• Primary Citation of Related Structures:  
  6UZD, 6UZE, 6UZB, 6PSN


• PubMed Abstract: 
  

Following assembly, the anthrax protective antigen (PA) forms an oligomeric translocon that unfolds and translocates either its lethal factor (LF) or edema factor (EF) into the host cell. Here, we report the cryo-EM structures of heptameric PA channels with partially unfolded LF and EF at 4.6 and 3.1-Å resolution, respectively. The first α helix and β strand of LF and EF unfold and dock into a deep amphipathic cleft, called the α clamp, which resides at the interface of two PA monomers. The α-clamp-helix interactions exhibit structural plasticity when comparing the structures of lethal and edema toxins. EF undergoes a largescale conformational rearrangement when forming the complex with the channel. A critical loop in the PA binding interface is displaced for about 4 Å, leading to the weakening of the binding interface prior to translocation. These structures provide key insights into the molecular mechanisms of translocation-coupled protein unfolding and translocation.

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Organizational Affiliation: 

Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, 21201, USA. [e-mail].

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Protective antigen	A, B, C, D, E, F, G	735	Bacillus anthracis	Mutation(s): 0  Gene Names: pagA, pag, pXO1-110, BXA0164, GBAA_pXO1_0164
Find proteins for P13423 (Bacillus anthracis) Explore P13423  Go to UniProtKB:  P13423

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Calmodulin-sensitive adenylate cyclase	H, I	767	Bacillus anthracis	Mutation(s): 0  Gene Names: cya, pXO1-122, BXA0141, GBAA_pXO1_0142 EC: 4.6.1.1
Find proteins for P40136 (Bacillus anthracis) Explore P40136  Go to UniProtKB:  P40136

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	A, B, C, D, E, F, G	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.40 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History & Funding Information

Deposition Data

• Deposited Date: 2019-11-14 
• Released Date: 2020-03-04 
Deposition Author(s): Hardenbrook, N.J., Liu, S., Zhou, K., Zhou, Z.H., Krantz, B.A.

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Funding Organization	Location	Grant Number
National Science Foundation (NSF, United States)	United States	DMR-1548924
National Institutes of Health/National Center for Research Resources (NIH/NCRR)	United States	R01GM071940/AI094386/DE025567
National Institutes of Health/National Center for Research Resources (NIH/NCRR)	United States	R21AI124020

Revision History 

• Version 1.0: 2020-03-04
  Type: Initial release