Antimicrobial peptides (AMPs) mainly introduced as a new generation of antibiotics, could be used for broad medical and biotechnological applications including treatment of multi drug resistant bacterial infections, anti-biofilm agents, wound healing, drug delivery and biosensors. High cost of peptide synthesis is one of the major obstacles of industrial scale production of AMPs. Recombinant expression of tandem repeats (multimeric forms) of AMPs with proper linkers is a useful approach for overcoming the high cost of peptides synthesis. In the present study, the effect of using glycine- serine [(GGGGS) 3] and aspartic acid-proline (DP) Linkers between four tandem repeats of sushi S3 antimicrobial peptide on its biological activity was investigated. S3 peptide, derived from factor C of horseshoe crab hemolymph has been known as a promising candidate as anti-Gram negative bacterial agent. Each variant of S3 tetramers with (GGGGS) 3 and DP linkers (named S3-4mer-GS and S3-4mer-DP, respectively) were expressed in E. coli. BL21 (DE3) as inclusion bodies and were purified by using immobilized metal affinity chromatography (IMAC). Antimicrobial activities and cytotoxic properties of variants were evaluated by determination of minimum inhibitory concentration assay (MIC) and MTT assay. Statistical analysis revealed that glycine serine linker improved antimicrobial activity of S3-tetramer approximately 25% and 86% in comparison to tetramer with aspartic acid - proline linker and S3 monomer respectively. According to the enhanced antibacterial activity of glycine- serine linker without any significant effects on its cytotoxicity, this linker will be a good choice for recombinant tandem expression of small antimicrobial peptides.

主要作为新一代抗生素引入的抗菌肽（AMPs）可用于广泛的医学和生物技术应用，包括治疗多种耐药细菌感染，抗生物膜剂，伤口愈合，药物输送和生物传感器。肽合成的高成本是工业规模生产AMP的主​​要障碍之一。具有适当接头的AMP串联重复序列（多聚体形式）的重组表达是克服肽合成成本高的有用方法。在本研究中，研究了寿司S3抗菌肽的四个串联重复序列之间使用甘氨酸-丝氨酸[（GGGGS）3]和天冬氨酸-脯氨酸（DP）接头对其生物学活性的影响。S3肽 衍生自马蹄蟹血淋巴因子C的抗革兰氏阴性细菌制剂有望成为有前途的候选药物。具有（GGGGS）3和DP接头的S3四聚体的每个变体（分别命名为S3-4mer-GS和S3-4mer-DP）表示为大肠杆菌。BL21（DE3）作为包涵体，并通过固定化金属亲和层析（IMAC）进行纯化。通过确定最小抑菌浓度测定（MIC）和MTT测定来评估变体的抗菌活性和细胞毒性。统计分析表明，与具有天冬氨酸的脯氨酸连接体和S3单体的四聚体相比，甘氨酸丝氨酸连接体可将S3-四聚体的抗菌活性提高约25％和86％。根据甘氨酸-丝氨酸接头的增强的抗菌活性而对其细胞毒性没有任何显着影响，该接头将是重组串联表达小抗菌肽的好选择。