9QCM

Botulinum neurotoxin type B1, 14-subunit, Large Progenitor Toxin Complex (L-PTC)

This is a non-PDB format compatible entry.

Summary for 9QCM

• Entry DOI: 10.2210/pdb9qcm/pdb
• EMDB information: 53015
• Descriptor: Botulinum neurotoxin type B, Botulinum neurotoxin type B1, nontoxic-nonhemagglutinin component, NTNH, Hemagglutinin component HA70, ... (5 entities in total)
• Functional Keywords: progenitor-toxin complex, botulinum neurotoxin, hemagglutinin, toxin
• Biological source: Clostridium botulinum; More
• Total number of polymer chains: 14
• Total formula weight: 757934.29

Authors

Krc, A.,Persson Kosenina, S.,Masuyer, G.,Stenmark, P. (deposition date: 2025-03-04, release date: 2025-09-10)

Primary citation

Krc, A.,Kosenina, S.P.,Nowakowska, M.B.,Masuyer, G.,Stenmark, P.
Structure of the complete 14-subunit botulinum neurotoxin B complex reveals a unique anchoring through the narrow central pore of HA70.
Sci Adv, 11:eadx5058-eadx5058, 2025

PubMed Abstract: Botulinum neurotoxin serotype B1 (BoNT/B) is a highly potent neurotoxin and therapeutic agent. Here, we present the structure of the complete 14-subunit (780 kDa) progenitor toxin complex (L-PTC) and of five subcomplexes. The structures show how the toxin interacts with its associated components in their role to protect and deliver BoNT/B across epithelial barriers. Each subcomplex, including the M-PTC, M-PTC-HA70, NTNH-HA70, and HA70 trimer, provides detailed understanding of the assembly mechanism, in which the NTNH-nLoop adopts a unique fold that locks the M-PTC into a central pore formed by HA70. The HA subcomplex presents a tripod architecture with flexible legs that may adapt to the rugged cell surface. Mass photometry reveals the pH dependence of BoNT/B release from the complex which is unexpectedly influenced by the presence of HA70. This study provides the complete L-PTC structure, offering insights into its assemblage and supporting the development of countermeasures and therapeutic applications.

PubMed: 40864696
DOI: 10.1126/sciadv.adx5058

Experimental method

ELECTRON MICROSCOPY (2.9 Å)