The plasmid carrying the PcTS1 gene was introduced into E. coli BL21Gold(DE3) for expression. The transformed E. coli strain was cultured in LB medium supplemented with kanamycin (50 mg/mL) for antibiotic selection. Cultures were set up in four flasks, each containing 1 L of LB, and incubated at 37 °C with continuous shaking at 220 rpm until the OD600 reached 0.8. Gene expression was induced by adding IPTG at a final concentration of 0.35 mM. The cultures were then incubated at 16 °C for 16 hours with shaking at 200 rpm. Following cultivation, the cells were harvested by centrifugation at 4000 rpm for 10 minutes at 4 °C. The cell pellet was resuspended in a cold lysis buffer (50 mM Tris-HCl, pH 8.0, with 150 mM NaCl). The cells were then disrupted using a High-Pressure Homogenizer (Scientz) and subsequently centrifuged at 18,000 g for 40 min at 4 °C. The supernatant containing the target proteins underwent nickel affinity chromatography, being loaded onto a column packed with Ni Sepharose Fast Flow (Cytiva). The column was washed with lysis buffer containing 20 mM imidazole and eluted with lysis buffer containing 500 mM imidazole. The purified proteins were promptly desalted using a PD-10 column (Cytiva), then rapidly frozen in liquid nitrogen, and stored at -80 °C until required. Protein purity was evaluated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).