Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia.
Biopolymers. 2009;92(6):554-64. doi: 10.1002/bip.21311.
The membrane interaction of two beta peptides was studied using a surface plasmon resonance biosensor. The two peptides are beta-17, a novel beta-amino acid based antimicrobial peptide and the corresponding scrambled-beta17--a non-antimicrobial beta-peptide analogue. Membrane interaction studies were performed with a series of phospholipid mixtures which mimic either mammalian cells (high in phosphatidylcholine and cholesterol) or microbial cells (high in phosphatidylethanolamine and phosphatidylglycerol). The results were compared with the membrane binding of the well-characterized antimicrobial peptide magainin 2. The secondary structure of these peptides were also determined in each lipid mixture by circular dichroism and correlated with the membrane-binding properties. Both beta-17 and the scrambled peptide have the same peptide length, charge and showed a similar secondary structure in both aqueous buffer and in the presence of liposomes. Both peptides also bound to a similar level on each membrane mixture, showing that the dramatic difference in biological activity is not based on the amount of peptide bound but rather differences in the degree of insertion and rate of membrane dissociation. Although beta-17 and the scrambled beta-17 peptide exhibited similar binding properties on all membrane mimics, both beta-peptides bound more to all membranes compared with magainin 2. Overall, the results further reveal the significant interplay between peptide amphipathicity and secondary structure induction on membrane binding.
使用表面等离子体共振生物传感器研究了两种β肽的膜相互作用。这两种肽是β-17，一种新型的基于β-氨基酸的抗菌肽和相应的无抗菌活性的β-肽类似物β17 。用一系列模拟哺乳动物细胞（高含量的磷脂酰胆碱和胆固醇）或微生物细胞（高含量的磷脂酰乙醇胺和磷脂酰甘油）的磷脂混合物进行了膜相互作用研究。将结果与具有良好特征的抗菌肽magainin 2 的膜结合进行了比较。还通过圆二色性确定了这些肽在每种脂质混合物中的二级结构，并将其与膜结合特性相关联。β-17 和 scrambled 肽具有相同的肽长度、电荷，并且在水缓冲液中和在脂质体存在下表现出相似的二级结构。这两种肽也在每种膜混合物上以相似的水平结合，表明生物活性的巨大差异不是基于结合的肽的量，而是插入的程度和膜解离的速率的差异。尽管β-17 和 scrambled β-17 肽在所有膜模拟物上表现出相似的结合特性，但与 magainin 2 相比，这两种β-肽与所有膜的结合都更多。总的来说，这些结果进一步揭示了肽的两亲性和二级结构诱导在膜结合中的重要相互作用。
