7NA9

Crystal structure of BoNT/B-LC-JSG-C1

Summary for 7NA9

• Entry DOI: 10.2210/pdb7na9/pdb
• Descriptor: Botulinum neurotoxin type B, JSG-C1, 1,2-ETHANEDIOL, ... (5 entities in total)
• Functional Keywords: neurotoxin, enzyme, inhibitor, antitoxin, toxin
• Biological source: Clostridium botulinum; More
• Total number of polymer chains: 2
• Total formula weight: 66163.26

Authors

Lam, K.,Jin, R. (deposition date: 2021-06-20, release date: 2021-12-22, Last modification date: 2023-10-18)

Primary citation

Lam, K.H.,Tremblay, J.M.,Perry, K.,Ichtchenko, K.,Shoemaker, C.B.,Jin, R.
Probing the structure and function of the protease domain of botulinum neurotoxins using single-domain antibodies.
Plos Pathog., 18:e1010169-e1010169, 2022

PubMed Abstract: 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.

PubMed: 34990480
DOI: 10.1371/journal.ppat.1010169

Experimental method

X-RAY DIFFRACTION (1.76 Å)