Čujová Sabína, Bednárová Lucie, Slaninová Jiřina, Straka Jakub, Čeřovský Václav
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic; Faculty of Science, Department of Biochemistry, Charles University in Prague, Hlavova 8, 12843, Prague 2, Czech Republic.
J Pept Sci. 2014 Nov;20(11):885-95. doi: 10.1002/psc.2681. Epub 2014 Aug 14.
The peptide named codesane (COD), consisting of 18 amino acid residues and isolated from the venom of wild bee Colletes daviesanus (Hymenoptera : Colletidae), falls into the category of cationic α-helical amphipathic antimicrobial peptides. In our investigations, synthetic COD exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and Candida albicans but also noticeable hemolytic activity. COD and its analogs (collectively referred to as CODs) were studied for the mechanism of their action. The interaction of CODs with liposomes led to significant leakage of calcein entrapped in bacterial membrane-mimicking large unilamellar vesicles made preferentially from anionic phospholipids while no calcein leakage was observed from zwitterionic liposomes mimicking membranes of erythrocytes. The preference of CODs for anionic phospholipids was also established by the blue shift in the tryptophan emission spectra maxima when the interactions of tryptophan-containing COD analogs with liposomes were examined. Those results were in agreement with the antimicrobial and hemolytic activities of CODs. Moreover, we found that the studied peptides permeated both the outer and inner cytoplasmic membranes of Escherichia coli. This was determined by measuring changes in the fluorescence of probe N-phenyl-1-naphthylamine and detecting cytoplasmic β-galactosidase released during the interaction of peptides with E. coli cells. Transmission electron microscopy revealed that treatment of E. coli with one of the COD analogs caused leakage of bacterial content mainly from the septal areas of the cells.
名为可待因(COD)的肽由18个氨基酸残基组成,从野生蜜蜂戴维斯集蜂(膜翅目:集蜂科)的毒液中分离得到,属于阳离子α-螺旋两亲性抗菌肽。在我们的研究中,合成的COD对革兰氏阳性菌、革兰氏阴性菌和白色念珠菌均表现出抗菌活性,但也具有明显的溶血活性。我们研究了COD及其类似物(统称为CODs)的作用机制。CODs与脂质体的相互作用导致包裹在主要由阴离子磷脂制成的模拟细菌膜的大单层囊泡中的钙黄绿素大量泄漏,而在模拟红细胞膜的两性离子脂质体中未观察到钙黄绿素泄漏。当检测含色氨酸的COD类似物与脂质体的相互作用时,色氨酸发射光谱最大值的蓝移也证实了CODs对阴离子磷脂的偏好。这些结果与CODs的抗菌和溶血活性一致。此外,我们发现所研究的肽可穿透大肠杆菌的外膜和内膜。这是通过测量探针N-苯基-1-萘胺的荧光变化以及检测肽与大肠杆菌细胞相互作用期间释放的细胞质β-半乳糖苷酶来确定的。透射电子显微镜显示,用一种COD类似物处理大肠杆菌会导致细菌内容物主要从细胞的隔膜区域泄漏。