5VGX

Structure of the C. botulinum neurotoxin serotype A with Hg bound


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.196 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Metal Ions Effectively Ablate the Action of Botulinum Neurotoxin A.

Bremer, P.T.Pellett, S.Carolan, J.P.Tepp, W.H.Eubanks, L.M.Allen, K.N.Johnson, E.A.Janda, K.D.

(2017) J. Am. Chem. Soc. 139: 7264-7272

  • DOI: 10.1021/jacs.7b01084
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Botulinum neurotoxin serotype A (BoNT/A) causes a debilitating and potentially fatal illness known as botulism. The toxin is also a bioterrorism threat, yet no pharmacological antagonist to counteract its effects has reached clinical approval. Existi ...

    Botulinum neurotoxin serotype A (BoNT/A) causes a debilitating and potentially fatal illness known as botulism. The toxin is also a bioterrorism threat, yet no pharmacological antagonist to counteract its effects has reached clinical approval. Existing strategies to negate BoNT/A intoxication have looked to antibodies, peptides, or organic small molecules as potential therapeutics. In this work, a departure from the traditional drug discovery mindset was pursued, in which the enzyme's susceptibility to metal ions was exploited. A screen of a series of metal salts showed marked inhibitory activity of group 11 and 12 metals against the BoNT/A light chain (LC) protease. Enzyme kinetics revealed that copper (I) and (II) cations displayed noncompetitive inhibition of the LC (Ki ≈ 1 μM), while mercury (II) cations were 10-fold more potent. Crystallographic and mutagenesis studies elucidated a key binding interaction between Cys165 on BoNT/A LC and the inhibitory metals. As potential copper prodrugs, ligand-copper complexes were examined in a cell-based model and were found to prevent BoNT/A cleavage of the endogenous protein substrate, SNAP-25, even at low μM concentrations of complexes. Further investigation of the complexes suggested a bioreductive mechanism causing intracellular release of copper, which directly inhibited the BoNT/A protease. In vivo experiments demonstrated that copper (II) dithiocarbamate and bis(thiosemicarbazone) complexes could delay BoNT/A-mediated lethality in a rodent model, indicating their potential for treating the harmful effects of BoNT/A intoxication. Our studies illustrate that metals can be therapeutically viable enzyme inhibitors; moreover, enzymes that share homology with BoNT LCs may be similarly targeted with metals.


    Organizational Affiliation

    Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Botulinum neurotoxin type A
A
441Clostridium botulinum (strain Hall / ATCC 3502 / NCTC 13319 / Type A)Mutation(s): 1 
Gene Names: botA (bna)
Find proteins for P0DPI1 (Clostridium botulinum (strain Hall / ATCC 3502 / NCTC 13319 / Type A))
Go to UniProtKB:  P0DPI1
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
HG
Query on HG

Download SDF File 
Download CCD File 
A
MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.196 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 49.449α = 90.00
b = 66.677β = 98.92
c = 65.115γ = 90.00
Software Package:
Software NamePurpose
PHENIXphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesR01AI119564

Revision History 

  • Version 1.0: 2017-05-31
    Type: Initial release
  • Version 1.1: 2017-06-14
    Type: Database references
  • Version 1.2: 2017-09-20
    Type: Author supporting evidence