【作者】 陆婕； 汪俊汉； 钟雅； 赵燕英； 陈正望；

【Author】 Jie Lu,Zheng-wang Chen~* Key Laboratory of Molecular Biophysics of the Ministry of Education,Institute of Biophysical and Biochemistry,College of Life Science and Technology,Huazhong University of Science and Technology, Wuhan,430074,China

【机构】 华中科技大学生命科学与技术学院生物物理与生物化学研究所； 华中科技大学附属医院；

【摘要】 家蝇抗菌肽多是碱性蛋白,目前尚无弱酸性家蝇抗菌肽的报道。通过稀醋酸低温浸提,海藻酸吸附,稀盐酸低温洗脱、盐析、Sephadex625凝胶过滤和CMC23弱阳离子交换柱层析等方法,利用灵敏的杀菌活性检测手段,从家蝇蛆（Musca domestica larvae）中分离纯化出一组弱酸性抗菌肽,对苏云金芽孢杆菌（Bacillus thuringiensis）等革兰氏阳性菌和几种革兰氏阴性菌有强烈的杀灭作用,有极强的耐热、耐冻融的特性。通过电洗脱方法进一步纯化出抗菌肽MD₇₀₉₅,质谱测定其分子量7095Da,IEF电泳测得其等电点5.59,经肽质量指纹谱（PMF）鉴定为一新肽。扫描电镜超微结构观察表明,弱酸性家蝇蛆抗菌肽对苏云金芽孢杆菌的杀菌机制主要是使细胞膜穿孔,内容物外泄,最终使细菌完全解体死亡。更多还原

【Abstract】 We report herein the isolation and characterization of a novel glycine-rich antimicrobial peptide purified from the larvae of Drosophila virilis.A range of chromatographic methods was used for isolation and its antibacterial activity against Bacillus subtilis was employed to screen for the most active fractions. The peptide,termed SK84 due to its N-terminal serine,C-terminal lysine and a total of 84 residues,was completed sequenced using RT-PCR cDNA cloning.SK84 contains a high level of glycine(15.5%)and a hexaglycine cluster motif in the N-terminal part.SK84 displayed antibacterial activity against the tested Gram-positive bacteria(Bacillus subtilis,Bacillus thuringiensis and Staphylococcus aureus),but had no effect on Gram-negative bacteria(Pseudomonas aeruginosa,Escherichia coli)and fungi(Saccharomyces cerevisiae,Candida albicans).SK84 had specific inhibitory effects on the proliferation of several cancer cell lines(Human leukemia THP-1,liver cancer HepG2,and breast cancer MCF-7 cells),but no hemolytic activity.The results from scanning electron microscopy observations revealed that SK84 killed THP-1 cells by destroying the cell membranes.Alignment results show that SK84 is a mature protein processed from the pseudoprotein GJ19999 from Drosophila virilis,and is very similar to several pseudoproteins from different Drosophila species.Our results show that SK84 represents a novel glycine-rich peptide family in Drosophila species with antimicrobial and anti-cancer cell activities.更多还原