两性多肽结构影响鲍曼不动杆菌外膜通透性的实验研究*两性多肽结构影响鲍曼不动杆菌外膜通透性的实验研究

目的：明确两性多肽结构对鲍曼不动杆菌（AB）外膜通透性的影响。方法 PCR扩增LysAB3基因及删除两性多肽结构的LysAB3-D基因,以pET28a（＋）为载体构建重组质粒,在大肠杆菌BL21（DE3）中表达LysAB3及LysAB3-D ,金属离子螯合亲和层析法纯化重组蛋白。将AB分别经LysAB3及LysAB3-D处理后,用扫描电子显微镜观察菌体形态,荧光显微镜观察菌体中是否有绿色荧光的聚集。结果经LysAB3处理后的AB ,在扫描电子显微镜下可见菌体表面粗糙、皱缩,部分裂解为碎片;在荧光显微镜下可见菌体内有绿色荧光聚集。而删除两性多肽结构的LysAB3-D作用AB后,却没有上述现象的发生。结论两性多肽结构可增加AB外膜通透性,有助于裂解酶进入其中,达到抗菌目的。

Effects of the amphiphilic peptides on membrane permeability of Acinetobacter baumannii

Objective To investigate effects of the amphiphilic peptides on membrane permeability of acinetobacter bauman-nii .Methods The LysAB3 and LysAB3-D (lack of amphiphilic peptides structure gene) was synthesized and inserted into the vec-tor pET28a(+ ) to construct the recombinant expression plasmid (pET28a-LysAB3 ,pET28a-LysAB3-D) .After expression in E . coli BL21(DE3) and purification with Ni2+-NTA Sepharose .Acinetobacter baumannii was observed by scanning electron microsco-py and fluorescence microscope ,pretreated with LysAB3 and LysAB3-D respectively .Results Under scanning electron microscopy , LysAB3-treated acinetobacter baumannii exhibited not only significant abnormalities ,including deep roughening of the cell surface , but also FITC readily accumulated in bacteria .It was different from LysAB3-D-treated .Conclusion These results indicate that the amphiphilic peptides structure increase membrane permeability of acinetobacter baumannii ,which helps LysAB3 degrade bacteria .