In this paper, the influence to bacterial surface characteristics and interaction mode with liposomes of antimicrobial peptides BF2-A and BF2-B, two analogues of Buforin Ⅱ, had been researched. The both peptides could enhance the electronegativity and hydrophobicity of cell surface of Gram-positive bacteria and Gram-negative bacteria, which determined by Zeta potential electrometer and hexadecane extraction, respectively. BF2-A/B could cause calcein release from large unilamellar liposomes consisted of the anionic lipid phosphatidylglycerol and the zwitteronic lipid phosphatidylcholine, which reflected the compositions of bacterial cytoplasmic membrane. BF2-A displayed much weaker leakage than that of BF2-B, suggesting that BF2-B might cause perturbation of the phospholipid bilayer of the plasma membrane. However, BF2-A/B didn't collapse the membrane of liposomes. Then the peptides were labeled with FITC. The blue shift of fluorescence spectra and the augmentation of quantum yield of FITC-peptides were discovered after the addition of liposomes. And the fluorescence quenching of FITC-peptides by acrylamide was prevented under the protection of liposomes, which implied that the N-terminal of BF2-A/B inserted into the phospholipid bilayer of membrane.%研究抗菌肽BuforinⅡ的衍生肽BF2-A/B对细菌表面特性的影响,以及与脂质体的作用模式.Zeta电位仪和十六烷萃取法检测发现BF2-A/B作用G<'->菌和G<'+>菌后,能够提高细胞表面电负性和疏水性.选用卵磷脂和心磷脂制备包裹钙黄绿素的脂质体,模拟细菌胞膜,考察发现BF2-A/B能够引起荧光素从脂质体中泄漏,BF2-B对膜的扰动作用更大,引起的泄漏率比BF2-A高,但它们都不破裂脂质体膜.用FITC标记衍生肽,研究发现加入脂质体后,FITC-肽荧光光谱蓝移,量子产率增大,并且脂质体保护FITC-肽免受丙烯酰胺的荧光淬灭,说明BF2-A/B的N-端插入了脂质体的磷脂双分子层中.
展开▼
