Dathe M, Schümann M, Wieprecht T, Winkler A, Beyermann M, Krause E, Matsuzaki K, Murase O, Bienert M
Institute of Molecular Pharmacology, Berlin, Germany.
Biochemistry. 1996 Sep 24;35(38):12612-22. doi: 10.1021/bi960835f.
An amphipathic model peptide, KLALKLALKALKAAKLA-NH2, and its complete double D-amino acid replacement set was used to analyze the process of peptide binding at lipid vesicles of different surface charge and to determine the structure of the lipid-bound peptides using CD spectroscopy. The relationship between peptide helicity, model membrane permeability, and biological activity has been studied by dye release from liposomes and investigation of antibacterial and hemolytic activity. The accumulation of cationic KLAL peptides at and the membrane-disturbing effect on bilayers of high negative surface charge were found to be dominated by charge interactions. Independent of any structural propensity, the cationic peptide side chains bind to the anionic phosphatidylglycerol moieties. The charge interactions hold the peptides at the bilayer surface, where they may disturb preferentially lipid headgroup organization by formation of peptide-lipid clusters. In contrast, KLAL peptide interaction with bilayers of low negative surface charge is highly dependent on peptide helicity. With decreasing amounts of anionic phosphatidylglycerol in the bilayer the membrane-disturbing effect of KLAL and other helical analogs substantially increases despite drastically reduced binding affinity. Less helical peptides exhibit reduced bilayer-disturbing activity, showing that the hydrophobic helix domain is decisive for binding at and inducing permeability in membranes of low negative surface charge. It is suggested that hydrophobic interactions drive the penetration of the amphipathic peptide structure into the inner membrane region, thus disturbing the arrangement of the lipid acyl chains and causing local disruption. On the basis of the proposed model for membrane disturbance, interactions modulating antibacterial and hemolytic activity are discussed.
一种两亲性模型肽KLALKLALKALKAAKLA-NH2及其完全双D-氨基酸替代集被用于分析不同表面电荷的脂质囊泡上肽的结合过程，并使用圆二色光谱法确定脂质结合肽的结构。通过脂质体的染料释放以及抗菌和溶血活性研究，探讨了肽螺旋度、模型膜通透性和生物活性之间的关系。发现阳离子KLAL肽在高负表面电荷双层上的积累及其对双层的膜干扰作用主要由电荷相互作用主导。与任何结构倾向无关，阳离子肽侧链与阴离子磷脂酰甘油部分结合。电荷相互作用将肽固定在双层表面，在那里它们可能通过形成肽-脂质簇优先扰乱脂质头部基团的组织。相比之下，KLAL肽与低负表面电荷双层的相互作用高度依赖于肽螺旋度。尽管结合亲和力大幅降低，但随着双层中阴离子磷脂酰甘油含量的减少，KLAL和其他螺旋类似物的膜干扰作用显著增加。螺旋度较低的肽表现出降低的双层干扰活性，表明疏水螺旋结构域对于在低负表面电荷膜上的结合和诱导通透性起决定性作用。有人提出，疏水相互作用驱动两亲性肽结构渗透到内膜区域，从而扰乱脂质酰基链的排列并导致局部破坏。基于提出的膜干扰模型，讨论了调节抗菌和溶血活性的相互作用。
