Acta Veterinaria et Zootechnica Sinica ›› 2025, Vol. 56 ›› Issue (6): 2917-2926.doi: 10.11843/j.issn.0366-6964.2025.06.034

• Preventive Veterinary Medicine • Previous Articles     Next Articles

Prokaryotic Expression of the T6SS Effector Protein Tse1 and Its inhibitory Effect on Staphylococcus aureus

ZHANG Manqi(), ZHAO Bingyu(), WEN Ruru, ZHANG Jingwen, SUN Mengran, ZHAN Leyang, GOU Jingxuan, SONG Xiangjun*()   

  1. Anhui Key Laboratory of Veterinary Pathobiology and Disease Control, Hefei 230036, China
  • Received:2024-08-09 Online:2025-06-23 Published:2025-06-25
  • Contact: SONG Xiangjun E-mail:2086428668@qq.com;zhaobingyu320@136.com;sxj@ahau.edu.cn

Abstract:

Type Ⅵ secretion systems (T6SS) are widely found in Gram-negative bacteria, and its effector protein Tse1 plays an important role in bacterial interspecies competition. The aim of this study was to investigate the inhibitory effect of Tse1 on Staphylococcus aureus (S. aureus), and to explore its expression and effect in drug-resistant bacteria. Tse1 protein expression was induced and purified using an E.coli prokaryotic expression system containing the recombinant plasmid pET-28a-Tse1. The disruptive effect of the recombinant protein Tse1 on the cell wall of S. aureus was observed by fluorescence microscopy and scanning electron microscopy. Finally, the antibacterial activity of recombinant protein Tse1 against S. aureus and its combined effect with antibiotics were determined by agar pore diffusion inhibition test and micro broth dilution method. The results showed that the expression of Tse1 protein reached the highest level and existed in soluble form in the supernatant at 16 ℃ and IPTG concentration of 0.5 mmol·L-1 for 16 h. The relative molecular mass of the protein was about 22 ku. The co-culture of recombinant protein Tse1 with S. aureus revealed that the protein was bound to the surface of the bacterium and was able to disrupt the cell wall of the bacterium, and the extent of the disruption was shown in a dose. The degree of disruption was dose-dependent. The agar pore diffusion inhibition assay showed that the recombinant protein Tse1 had significant inhibitory effects on different strains of S. aureus, and the inhibitory effect of Tse1 protein could be significantly enhanced by the combination of penicillin (PG). In this experiment, the prokaryotic expression and purification method of Tse1 protein were established, and it was proved that Tse1 protein had an inhibitory effect on S. aureus, and its inhibitory effect could be enhanced by combining with penicillin, which provided the theoretical basis for the excavation of new antibiotic substitutes.

Key words: antibiotic substitution, T6SS, Tse1, Staphylococcus aureus

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