The search for effective and bioactive antimicrobial molecules to encounter the medical need for new antibiotics is an encouraging area of research. Plant defensins are small cationic, cysteine-rich peptides with a stabilized tertiary structure by disulfide-bridges and characterized by a wide range of biological functions. The heterologous expression of Egyptian maize defensin (MzDef) in Escherichia coli and subsequent purification by glutathione affinity chromatography yielded 2 mg/L of recombinant defensin peptide. The glutathione-S-transferase (GST)-tagged MzDef of approximately 30 kDa in size (26 KDa GST + ~ 4 KDa MzDef peptide) was immunodetected with anti-GST antibodies. The GST-tag was successfully cleaved from the MzDef peptide by thrombin, and the removal was validated by the Tris-Tricine gel electrophoresis. The MzDef induced strong growth inhibition of Rhizoctonia solani, Fusarium verticillioides, and Aspergillus niger by 94.23%, 93.34%, and 86.25%, respectively, whereas relatively weak growth inhibitory activity of 35.42% against Fusarium solani was recorded. Moreover, strong antibacterial activities were demonstrated against E. coli and Bacillus cereus and the moderate activities against Salmonella enterica and Staphylococcus aureus at all tested concentrations (0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 µM). Furthermore, the in vitro MTT assay exhibited promising anticancer activity against all tested cell lines (hepatocellular carcinoma, mammary gland breast cancer, and colorectal carcinoma colon cancer) with IC₅₀ values ranging from 14.85 to 29.85 µg/mL. These results suggest that the recombinant peptide MzDef may serve as a potential alternative antimicrobial and anticancer agent to be used in medicinal application.

寻找有效且具有生物活性的抗菌分子以满足新型抗生素的医疗需求是一个令人鼓舞的研究领域。植物防御素是富含半胱氨酸的小阳离子肽，具有通过二硫桥稳定的三级结构，具有广泛的生物功能。埃及玉米防御素 (MzDef) 在大肠杆菌中异源表达，随后通过谷胱甘肽亲和层析纯化，得到 2 mg/L 的重组防御素肽。使用抗 GST 抗体对大小约为 30 kDa 的谷胱甘肽-S-转移酶 (GST) 标记的 MzDef（26 KDa GST + ~ 4 KDa MzDef 肽）进行免疫检测。凝血酶成功地将 GST 标签从 MzDef 肽上切下，并通过 Tris-Tricine 凝胶电泳验证了去除效果。 MzDef 对立枯丝核菌、轮枝镰刀菌和黑曲霉的生长抑制作用分别为 94.23%、93.34% 和 86.25%，而对立枯镰刀菌的生长抑制活性相对较弱，为 35.42%。此外，还表现出了对大肠杆菌的强抗菌活性。在所有测试浓度（0.1、0.2、0.4、0.8、1.6 和 3.2 µM）下，对大肠杆菌和蜡样芽孢杆菌均具有中等活性，对肠沙门氏菌和金黄色葡萄球菌具有中等活性。此外，体外 MTT 测定对所有测试的细胞系（肝细胞癌、乳腺乳腺癌和结直肠癌结肠癌）均表现出良好的抗癌活性，IC ₅₀值范围为 14.85 至 29.85 µg/mL。 这些结果表明重组肽 MzDef 可作为潜在的替代抗菌剂和抗癌剂用于医学应用。