家蝇抗真菌肽衍生物MAF-1C抗白色念珠菌活性研究

Study on Canidia albicans activity of Musca domestica antifungal derivatives peptide-1C(MAF-1C)

[目的]探究家蝇抗真菌肽衍生物MAF-1C结构特点及抗白色念珠菌活性。[方法]采用氨基酸替代法设计MAF-1A衍生肽MAF-1C,生物信息学分析其理化特性,微量液体稀释法、菌落计数法检测体外抗白色念珠菌活性,扫描电镜观察对菌细胞结构的影响。[结果]MAF-1C为非跨膜阳离子线状多肽,带8个正电荷,二级结构以α螺旋为主。对白色念珠菌具有抗菌活性,MIC、MFC值分别为0.2 mg/m L和0.5 mg/m L,2×MIC浓度的MAF-1C从作用一开始就发挥抗菌作用,其作用后白色念珠菌细胞表面出现明显的凹陷、裂痕,之后细胞皱缩、裂解死亡,并且菌细胞损伤程度与肽浓度及作用时间呈正相关。[结论]MAF-1C结构参数及对白色念珠菌的抗菌活性均显著优于模板肽,对比模板肽改造后的肽阳离子电荷增加了6个,总平均疏水值(GRAVY)由-1.081升高到0.588,不稳定系数由42.27降低到5.83,MIC由0.6 mg/m L降低到0.2 mg/m L,MFC由0.7 mg/m L降低到0.5 mg/m L,其可通过破坏白色念珠菌细胞结构发挥抗菌作用。

[ Objective ] To explore Canidia Albicans （ C. albicans） activity and structure feature of Musca Domestica antifungal derivatives peptide - 1 C （MAF - 1 C）. [ Methods] The sequence of MAF - 1 A was used as template to develop novel antifungal peptides. A novel peptide, named MAF - 1 C, was designed based on the MAF - 1A. The structure feature of MAF - I C was ana- lyzed by the bioinformatics. Detection its antifungal activity by trace liquid dilution method, colony counting method. The uhra- structural observation of Candida albican~ exposing to the MIC concentration of MAF - 1C was also performed by Scanning E- lectron Microscopy method. [ Results] The results of bioinformatics analysis had showed that MAF - 1C without transmembrane structure, the secondary structure of MAF - 1C was α - helix, compared with MAF - 1 A, the helicity, two net positive charge, hydrophobicity rate and stability of MAF - 1C had enhanced. MAF - 1 C exhibited antifungal activity against C. albicans in vitro. The MIC and MFC were 0.2 mg/mL and 0.5 mg/mL respectively. MAF - 1C displayed effective antifungal activity a- gainst C. albicans from the beginning at concentration of 2 x MIC. Compared with the MAF - 1C free control group, the cell sur- face of C. albicans appeared the pathological changes in MAF - l C group, And the damage degree of bacteria cells was positive- ly correlated with the concentration of peptide and the time of action. [ ~onclusion] MAF - 1 C was a linear cationic polypeptide with abundant o~ - helix and had an antifungal activity against C. albicans through interference with the cell surface structure. Structural parameters and the antifungal activity against C. albicans of MAF - 1 C were better than template peptide, Compared template peptide, after the transformation,ion charge is increased to 6, GRAVY is increased from - 1.081 to 0. 588, instability coefficient is reduced from 42.27 to 5.83, MIC is reduced from O. 6 mg/mL to 0.2 mg/mL, MFC is reduced from 0.7 mg/mL to O. 5 mg,/mL.