8CQ0 image
Entry Detail
PDB ID:
8CQ0
EMDB ID:
Keywords:
Title:
Photorhabdus luminescens TcdA1 prepore-to-pore intermediate, K567W K2008W mutant
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-03-03
Release Date:
2024-03-13
Method Details:
Experimental Method:
Resolution:
3.20 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:TcdA1
Mutations:K567W K2008W
Chain IDs:A, B, C, D, E
Chain Length:2535
Number of Molecules:5
Biological Source:Photorhabdus luminescens
Ligand Molecules
Primary Citation
Multistate kinetics of the syringe-like injection mechanism of Tc toxins.
Sci Adv 11 eadr2019 eadr2019 (2025)
PMID: 39752508 DOI: 10.1126/sciadv.adr2019

Abstact

Tc toxins are pore-forming virulence factors of many pathogenic bacteria. Following pH-induced conformational changes, they perforate the target membrane like a syringe to translocate toxic enzymes into a cell. Although this complex transformation has been structurally well studied, the reaction pathway and the resulting temporal evolution have remained elusive. We used an integrated biophysical approach to monitor prepore-to-pore transition and found a reaction time of ~30 hours for a complete transition. We show two asynchronous general steps of the process, shell opening and channel ejection, with the overall reaction pathway being a slow multistep process involving three intermediates. Liposomes, an increasingly high pH, or receptors facilitate shell opening, which is directly correlated with an increased rate of the prepore-to-pore transition. Channel ejection is a near-instantaneous process which occurs with a transition time of <60 milliseconds. Understanding the mechanism of action of Tc toxins and unveiling modulators of the kinetics are key steps toward their application as biomedical devices or biopesticides.

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Primary Citation of related structures