7L6V image
Entry Detail
PDB ID:
7L6V
Keywords:
Title:
Crystal structure of BoNT/A-LC-JPU-A5-JPU-C1-JPU-H7-JPU-D12-ciA-F12
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2020-12-24
Release Date:
2021-12-22
Method Details:
Experimental Method:
Resolution:
2.01 Å
R-Value Free:
0.23
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:BoNT/A
Chain IDs:A
Chain Length:425
Number of Molecules:1
Biological Source:Clostridium botulinum
Polymer Type:polypeptide(L)
Description:JPU-C1
Chain IDs:B
Chain Length:122
Number of Molecules:1
Biological Source:Vicugna pacos
Polymer Type:polypeptide(L)
Description:JPU-A5
Chain IDs:C
Chain Length:127
Number of Molecules:1
Biological Source:Vicugna pacos
Polymer Type:polypeptide(L)
Description:JPU-H7
Chain IDs:D
Chain Length:122
Number of Molecules:1
Biological Source:Vicugna pacos
Polymer Type:polypeptide(L)
Description:Single-domain antibody VHH ciA-F12
Chain IDs:E
Chain Length:125
Number of Molecules:1
Biological Source:Vicugna pacos
Polymer Type:polypeptide(L)
Description:JPU-D12
Chain IDs:F
Chain Length:130
Number of Molecules:1
Biological Source:Vicugna pacos
Primary Citation
Probing the structure and function of the protease domain of botulinum neurotoxins using single-domain antibodies.
Plos Pathog. 18 e1010169 e1010169 (2022)
PMID: 34990480 DOI: 10.1371/journal.ppat.1010169

Abstact

Botulinum neurotoxins (BoNTs) are among the deadliest of bacterial toxins. BoNT serotype A and B in particular pose the most serious threat to humans because of their high potency and persistence. To date, there is no effective treatment for late post-exposure therapy of botulism patients. Here, we aim to develop single-domain variable heavy-chain (VHH) antibodies targeting the protease domains (also known as the light chain, LC) of BoNT/A and BoNT/B as antidotes for post-intoxication treatments. Using a combination of X-ray crystallography and biochemical assays, we investigated the structures and inhibition mechanisms of a dozen unique VHHs that recognize four and three non-overlapping epitopes on the LC of BoNT/A and BoNT/B, respectively. We show that the VHHs that inhibit the LC activity occupy the extended substrate-recognition exosites or the cleavage pocket of LC/A or LC/B and thus block substrate binding. Notably, we identified several VHHs that recognize highly conserved epitopes across BoNT/A or BoNT/B subtypes, suggesting that these VHHs exhibit broad subtype efficacy. Further, we identify two novel conformations of the full-length LC/A, that could aid future development of inhibitors against BoNT/A. Our studies lay the foundation for structure-based engineering of protein- or peptide-based BoNT inhibitors with enhanced potencies and cross-subtypes properties.

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