摘要
通过改变脂质体中磷脂成分，构建了不同电性的脂质体。利用表面活性剂介导方法，将截短的金黄色葡萄球菌细胞膜上的组氨酸激酶AgrC（ AgrCTM6-7C ）蛋白重构到不同电性的脂质体上。结果表明，阴离子脂质体对AgrCTM6-7C蛋白的镶嵌效率明显高于阳离子脂质体，约60%~70%镶嵌至阴离子脂质体中的AgrCTM6-7C蛋白的细胞质域朝向脂质体囊泡的外部，并保持较高活性。利用圆二色光谱比较了AgrCTM6-7C蛋白在表面活性剂胶束和脂质体中的二级结构稳定性，发现阴离子脂质体对AgrCTM6-7C蛋白的二级结构具有一定的保护作用，可明显提高蛋白的热稳定性。
AgrC is a membrane-embedded histidine kinase in Staphylococcus aureus that is thought to act as a sensor for the recognition of environmental signals and the transduction of signals into the cytoplasm so as to regulate and control a series of related pathogenic gene expression. However, for the complexity of cell mem-brane, it turns to be difficult to study AgrC on bacterial cell membrane directly. Many researches tried to take advantage of proteoliposome which could provide an approximate natural membrane environment and keep the protein activity to study the structure and function of membrane proteins. In order to build a transmembrane protein incorporation system with a relatively high incorporation efficiency, function activity and stability, various factors were considered, such as the impact of different charge polarity head on protein transmembrane incorporation efficiency. Here, four kinds of different charged liposomes were prepared by changing the phos-pholipid components in liposome and a detergent-mediated method was used to reconstitute truncated AgrC protein（AgrCTM6-7C） into them. The results showed that negatively charged liposomes leaded to a higher incor-poration efficiency compared with the positively charged one and about 60%-70% C-terminal cytoplasmic do-main of AgrCTM6-7C protein reconstituted into negatively charged liposomes were outside-orientated which re-mained a highly kinase activity. Furthermore, from circular dichroism detection result, we can draw a conclu-sion that liposome has certain protective effect on AgrCTM6-7C protein secondary structure and improve the ther-mal stability of the protein.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第9期1901-1907,共7页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:21272031)
大连民族学院研究生创新基金项目(批准号:YCX2013016)资助~~
