Download MendeleyAmidase and lysozyme dual functions in TseP reveal a new family of chimeric effectors in the type VI secretion system.
Wang, Z.H., An, Y., Zhao, T., Pei, T.T., Wang, D.Y., Liang, X., Qin, W., Dong, T.(2025) Elife 13
- PubMed: 40063082 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.7554/eLife.101125
- Primary Citation Related Structures:
8XCL - PubMed Abstract:
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 TseP C4+ 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.
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
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