Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China.
Laboratory of Molecular Nutrition and Immunity, The Institute of Animal Nutrition, Northeast Agricultural University, Harbin, PR China.
Biomaterials. 2014 Sep;35(27):8028-39. doi: 10.1016/j.biomaterials.2014.06.005. Epub 2014 Jun 19.
Because antimicrobial peptides (AMPs) are potentially useful for the treatment of multidrug-resistant infections, more attention is being paid to the structural modification and structure-function relationship of both naturally occurring and synthetic AMPs. Previous studies indicated that Protegrin-1 (PG-1), isolated from porcine leukocytes, exhibited considerable antimicrobial activity and cytotoxicity. The β-turn of PG-1 floated on the surface of bacterial membrane, while its β-strand inserted into the bacterial membrane and formed pores that were dedicated to producing cytotoxicity. For reducing cytotoxicity and improving cells selectivity, we designed a series of simplified symmetric-end peptides by combining the β-turn of PG-1 with simple amino acid repeat sequences. The sequence of designed symmetric-end peptides is (XR)nH(RX)n, (n = 1,2; X represents I, F, W and P; H represents CRRRFC). The symmetric-end peptides displayed antimicrobial activity against both gram-positive and gram-negative bacteria. In particular, (XR)2H(RX)2 (X here is I, F and W) showed greater antimicrobial potency than PG-1. Hemolysis activity and cytotoxicity, detected by using human red blood cells (RBCs) and human embryonic lung fibroblasts MRC-5 cells, were observably lower than the native peptide PG-1. (IR)2H(RI)2 (IR2), folded into β-sheet structures, displayed the highest therapeutic index, suggesting its great cell selectivity. The fluorescence spectroscopy, flow cytometry, and electron microscopy observation indicated that IR2 exhibited great membrane penetration potential by inducing membrane blebbing, disruption and lysis. Collectively, generating symmetric-end β-sheet peptides is a promising strategy for designing effective AMPs with great antimicrobial activities and cell selectivity.
由于抗菌肽（AMPs）在治疗多重耐药感染方面具有潜在的应用价值，因此人们越来越关注天然和合成 AMP 的结构修饰和结构-功能关系。先前的研究表明，从猪白细胞中分离出的 Protegrin-1（PG-1）具有相当大的抗菌活性和细胞毒性。PG-1 的β-转角漂浮在细菌膜的表面，而其β-折叠插入细菌膜并形成孔，专门用于产生细胞毒性。为了降低细胞毒性并提高细胞选择性，我们通过将 PG-1 的β-转角与简单的氨基酸重复序列相结合，设计了一系列简化的对称端肽。设计的对称端肽的序列为（XR）nH（RX）n，（n=1,2；X 代表 I、F、W 和 P；H 代表 CRRRFC）。这些对称端肽显示出对革兰氏阳性和革兰氏阴性细菌的抗菌活性。特别是，（XR）2H（RX）2（X 在这里是 I、F 和 W）比 PG-1 表现出更强的抗菌效力。用人类红细胞（RBC）和人胚肺成纤维细胞 MRC-5 细胞检测到的溶血活性和细胞毒性明显低于天然肽 PG-1。（IR）2H（RI）2（IR2），折叠成β-折叠结构，显示出最高的治疗指数，表明其具有很好的细胞选择性。荧光光谱、流式细胞术和电子显微镜观察表明，IR2 通过诱导膜泡形成、破坏和裂解，表现出很强的膜穿透潜力。总之，生成对称端β-折叠肽是设计具有高效抗菌活性和细胞选择性的有效 AMP 的一种很有前途的策略。
