Dong Zhu, Luo Wenjie, Zhong Hengren, Wang Manchuriga, Song Yanting, Deng Shiming, Zhang Yingxia
Key Laboratory of Tropical Biological Resources, Ministry of Education, College of Marine Science, Hainan University, Haikou 570228, China.
Hainan Key Laboratory of Tropical Animal Reproduction & Breeding and Epidemic Disease Research, Hainan University, Haikou 570228, China.
Acta Biochim Biophys Sin (Shanghai). 2017 May 1;49(5):450-457. doi: 10.1093/abbs/gmx023.
The cDNAs encoding antimicrobial peptides (AMPs) in the skin of Hylarana guentheri were identified, namely temporin (five peptides, termed temporin-GHa-GHd and temporin-GUa), brevinin-1 (one peptide, brevinin-1GUb), and brevinin-2 (eight peptides, brevinin-2GHd-2GHj, and brevinin-2GHb). Eleven of the 14 peptides have novel primary structures. Synthesized temporin GHa-GHd have broad-spectrum antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli, Vibrio alginolyticus, and Pseudomonas aeruginosa), as well as fungus (Candida albicans). Among these tested strains, S. aureus was the most sensitive to temporin-GHa-GHd with minimum inhibitory concentration (MIC) values between 6.8 and 12.9 μM. They also exhibited antimicrobial activities against Methicillin-resistant S. aureus with the MIC ranging from 12.7 to 51.7 μM. Interestingly, secondary structure prediction shows that there is no α-helix in temporin-GHb, which illustrates that α-helix is not required for the antimicrobial activity of temporin-GHb. NaCl (at final concentrations of 0.15-2 M) decreased the antimicrobial activity of temporin-GHa-GHd slightly, while human serum and S. aureus V8 proteinase had no effect on the antimicrobial activity. Scanning electron microscopy images of E. coli and S. aureus showed that the surface of microbial cells was considerably rough and shrived after 1 h of treatment with temporin-GHa-GHd at 37°C. The stabilities of temporin-GHa-GHd in human serum or in S. aureus V8 proteinase make them to be promising candidates of novel antimicrobial agents or models for the development of novel AMPs.
鉴定了滇蛙皮肤中编码抗菌肽（AMPs）的cDNA，即颞蛙素（5种肽，称为颞蛙素-GHa-GHd和颞蛙素-GUa）、铃蟾肽-1（1种肽，铃蟾肽-1GUb）和铃蟾肽-2（8种肽，铃蟾肽-2GHd-2GHj和铃蟾肽-2GHb）。14种肽中的11种具有新颖的一级结构。合成的颞蛙素GHa-GHd对革兰氏阳性菌（金黄色葡萄球菌和枯草芽孢杆菌）、革兰氏阴性菌（大肠杆菌、溶藻弧菌和铜绿假单胞菌）以及真菌（白色念珠菌）具有广谱抗菌活性。在这些测试菌株中，金黄色葡萄球菌对颞蛙素-GHa-GHd最敏感，最低抑菌浓度（MIC）值在6.8至12.9μM之间。它们对耐甲氧西林金黄色葡萄球菌也表现出抗菌活性，MIC范围为12.7至51.7μM。有趣的是，二级结构预测表明颞蛙素-GHb中没有α-螺旋，这说明α-螺旋对于颞蛙素-GHb的抗菌活性不是必需的。NaCl（终浓度为0.15 - 2 M）略微降低了颞蛙素-GHa-GHd的抗菌活性，而人血清和金黄色葡萄球菌V8蛋白酶对其抗菌活性没有影响。大肠杆菌和金黄色葡萄球菌的扫描电子显微镜图像显示，在37°C用颞蛙素-GHa-GHd处理1小时后，微生物细胞表面变得相当粗糙且皱缩。颞蛙素-GHa-GHd在人血清或金黄色葡萄球菌V8蛋白酶中的稳定性使其成为新型抗菌剂的有希望的候选者或开发新型抗菌肽的模型。
