Cyclization of a cytolytic amphipathic α-helical peptide and its diastereomer:: Effect on structure, interaction with model membranes, and biological function
Cyclization of a cytolytic amphipathic α-helical peptide and its diastereomer:: Effect on structure, interaction with model membranes, and biological function
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DOI：
10.1021/bi992408i
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发表时间：
2000-05-23
期刊：
影响因子：
2.9
通讯作者：
Shai, Y
中科院分区：
文献类型：
--
作者：
Oren, Z;Shai, Y
两亲性α螺旋结构被认为是一大群溶细胞肽具有裂解活性的先决条件。然而，尽管对各种参数对其结构和活性的贡献进行了大量研究，但线性的重要性尚未得到检验。在本研究中，我们从功能和结构上表征了线性两亲性α螺旋肽（wt肽）、其非对映异构体以及两者的环状类似物。使用具有相同疏水性和带正电氨基酸序列但具有不同形成螺旋结构倾向的类似物，我们能够检查线性对螺旋形成、生物学功能以及膜结合和渗透的贡献。重要的是，我们发现，与线性肽相比，环化通过显着降低环肽的溶血活性来增加细菌和人红细胞之间的选择性。此外，wt肽对革兰氏(+)细菌具有高度活性，而其环状对应物对革兰氏(+)和革兰氏(-)细菌均具有活性。这些发现与环状类似物与其线性对应物相比结合和渗透两性离子磷脂膜的能力受损以及环状wt肽对带负电的膜的结合和渗透活性的增加相关。此外，环化消除了线性野生型肽在溶液和SDS中的寡聚化，这表明可能存在另一个因素来解释线性和环状野生型肽之间抗菌活性谱的差异。有趣的是，衰减全反射傅立叶变换红外 (ATR-FTIR) 光谱显示，尽管沿着肽主链环化并掺入了 33% D-氨基酸，但膜环境可以在肽上强加主要的螺旋结构，这是其生物学功能所必需的。总的来说，我们的结果表明线性不是两亲性α-螺旋肽裂解活性的先决条件，而是影响革兰氏(+)和革兰氏-细菌之间以及哺乳动物细胞和细菌之间的选择性。此外，将 D-氨基酸掺入溶解肽及其环化的组合为开发一组新的抗菌肽开辟了道路，这些抗菌肽具有改善的治疗传染病的特性。
The amphipathic alpha-helical structure is considered to be a prerequisite for the lytic activity of a large group of cytolytic peptides. However, despite numerous studies on the contribution of various parameters to their structure and activity, the importance of linearity has not been examined. In the present study we functionally and structurally characterized a linear amphipathic alpha-helical peptide (wt peptide), its diastereomer, and cyclic analogues of both. Using analogues with the same sequence of hydrophobic and positively charged amino acids, but with different propensities to form a helical structure, we were able to examine the contribution of linearity to helix formation, bilogical function, and membrane binding and permeation. Importantly, we found that cyclization increases the selectivity between bacteria and human erythrocytes by substantially reducing the hemolytic activity of the cyclic peptides compared with the linear peptides. Moreover, whereas the wt peptide was highly active toward Gram(+) bacteria, its cyclic counterpart is active toward both Gram(+) and Gram(-) bacteria. These findings are correlated with an impaired ability of the cyclic analogues to bind and permeate zwitterionic phospholipid membranes compared with their linear counterparts and an increase in the binding and permeating activity of the cyclic wt peptide toward negatively charged membranes. Furthermore, cyclization abolished the oligomerization of the linear wt peptide in solution and in SDS, suggesting an additional factor that may account for the difference in the spectrum of antibacterial activity between the linear and the cyclic wt peptides. Interestingly, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy revealed that, despite cyclization and incorporation of 33% D-amino acids along the peptide backbone, the membrane environment can impose a predominantly helical structure on the peptides, which is required for their bilogical function. Overall, our results indicate that linearity is not a prerequisite for lytic activity of amphipathic alpha-helical peptides but rather affects the selectivity between Gram(+) and Gram- bacteria and between mammalian cells and bacteria. In addition, the combination of incorporating of D-amino acids into lytic peptides and their cyclization open the way for developing a new group of antimicrobial peptides with improved properties for treating infectious diseases.