动物源抗真菌肽CGA-N46降低真菌线粒体膜电位分子机制研究

针对病原真菌耐药性问题，研究新型抗真菌肽作用机制对新药开发具有重要意义。嗜铬粒蛋白A（CGA）N-端衍生肽CGA-N46是申请人发现的具有较高抗真菌活性的动物源抗菌肽。最近结题的国家自然科学基金项目“动物内源性多肽CGA-N46抗真菌作用机制研究”，发现CGA-N46能够降低克柔念珠菌线粒体膜电位，但对细胞膜没有影响，推测其作用位点新颖。抗菌肽降低线粒体膜电位分子机制迄今未见报道。该项目采用血卟啉荧光各向异性研究CGA-N46与线粒体膜蛋白结合对线粒体膜流动性的影响；采用透射电镜研究CGA-N46对线粒体通透性转换孔（mPTP）打开程度的影响；采用荧光光谱法、原子力显微镜和圆二色谱技术研究CGA-N46构型对线粒体膜通透性的影响，从线粒体膜流动性、mPTP打开程度和CGA-N46构型三方面阐明CGA-N46降低真菌线粒体膜电位的分子机制，为将CGA-N46开发成新型抗真菌药物奠定理论基础。

In the light of the drug resistance of fungi, the investigations of the molecular action mechanism of novel antifungal peptides are very important for the development of the antifungal drugs. CGA-N46, an innate derived peptide from chromogranin A, is an antifungal peptide found by our research group. From the results of the recently accomplished project "The action mechanism of the innate antifungal peptide CGA-N46" supported by the National Natural Science Foundation of China (NNSFC), our research group found that CGA-N46 could reduce the mitochondrial membrane potential of Candida krusei, but had no effect on the permeability of the cell membrane. A conclusion could be made that the antifungal action mechanism of CGA-N46 was specific and novel. Based on the results, the molecular action mechanism of CGA-N46 on the decrease of fungal mitochondrial membrane potential need to be further investigated. In the present project, The anisotropy changes of hematoporphyrin will be researched to reveal the effects of the binding of CGA-N46 with the mitochondrial membrane proteins on the mitochondrial fluidity. TEM will be used to study the osmotic volume changes of mitochondria to clarify the effects of CGA-N46 on the opening of mitochondrial permeability transition pore (mPTP). And fluorescent spectroscopy, atomic force microscope and circular dichroism will be used to research the effect of the structure of CGA-N46 on the permeability of mitochondria. In the end, the molecular action mechanism of CGA-N46 on the decrease of yeast mitochondrial membrane potential will be brought to life from the three aspects listed as above. The research of the project will support theoretical bases for the development of CGA-N46 to be a novel clinical candidate to cure fungal infections.