8XCL image
Entry Detail
PDB ID:
8XCL
Keywords:
Title:
Character of TseP: a dual functional effector of type VI secretion system
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-12-09
Release Date:
2025-04-23
Method Details:
Experimental Method:
Resolution:
2.27 Å
R-Value Free:
0.22
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:EF-hand domain-containing protein
Chain IDs:A
Chain Length:244
Number of Molecules:1
Biological Source:Aeromonas dhakensis
Primary Citation
Amidase and lysozyme dual functions in TseP reveal a new family of chimeric effectors in the type VI secretion system.
Elife 13 ? ? (2025)
PMID: 40063082 DOI: 10.7554/eLife.101125

Abstact

Peptidoglycan (PG) serves as an essential target for antimicrobial development. An overlooked reservoir of antimicrobials lies in the form of PG-hydrolyzing enzymes naturally produced for polymicrobial competition, particularly those associated with the type VI secretion system (T6SS). Here, we report that a T6SS effector TseP, from Aeromonas dhakensis, represents a family of effectors with dual amidase-lysozyme activities. In vitro PG-digestion coupled with LC-MS analysis revealed the N-domain's amidase activity, which is neutralized by either catalytic mutations or the presence of the immunity protein TsiP. The N-domain, but not the C-domain, of TseP is sufficient to restore T6SS secretion in T6SS-defective mutants, underscoring its critical structural role. Using pull-down and secretion assays, we showed that these two domains interact directly with a carrier protein VgrG2 and can be secreted separately. Homologs in Aeromonas hydrophila and Pseudomonas syringae exhibited analogous dual functions. Additionally, N- and C-domains display distinctive GC contents, suggesting an evolutionary fusion event. By altering the surface charge through structural-guided design, we engineered the TsePC4+ effector that successfully lyses otherwise resistant Bacillus subtilis cells, enabling the T6SS to inhibit B. subtilis in a contact-independent manner. This research uncovers TseP as a new family of bifunctional chimeric effectors targeting PG, offering a potential strategy to harness these proteins in the fight against antimicrobial resistance.

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