Fluorescent-labeled peptides were synthesized as antimicrobial peptide models for evaluating the peptide interaction with eukaryotic and bacterial lipid membrane models and their dynamics in lipid membrane by fluorescence techniques. In this work, we discuss the behavior of two peptides of 15 residues, C-PEP and PEP (C-PEP being labeled with a coumarin 343) synthesized employing the solid-phase methodology (SPPS). The interaction of these peptides with lipid membranes of different phospholipid composition was studied by steady-state and time-resolved fluorescence spectroscopy, steady-state and time-resolved fluorescence anisotropy and circular dichroism. Both peptides were random coil in an aqueous medium and change their conformation to an α-helix when they were incorporated into DOPC lipid bilayer. In this lipid membrane, the fluorophore-peptide (C-PEP) displayed membrane interaction with a slightly higher partition within the lipid bilayer in comparison with PEP; nevertheless, the secondary structure adopted within the lipid membrane was not significantly modified by the conjugation with the coumarin moiety. In DPPC:DOPC (50:50) liposomes both peptides were less partitioned, as the incorporation was hindered because the lipid membrane is less fluid. And in the liposomes made of POPE:POPG (70:30), a bacterial model lipid membrane, a larger partition constant was observed with the adoption of structures of polyproline II (PPII)-type. The minor conformational disruption as a result of the conjugation with the coumarin moiety would allow modeling the peptide dynamic interaction with membranes using fluorescence techniques.

合成了荧光标记的肽作为抗菌肽模型，用于通过荧光技术评估肽与真核和细菌脂质膜模型的相互作用及其在脂质膜中的动力学。在这项工作中，我们讨论了使用固相方法（SPPS）合成的15个残基的两种肽的行为，即C-PEP和PEP（C-PEP用香豆素343标记）。通过稳态和时间分辨荧光光谱，稳态和时间分辨荧光各向异性和圆二色性研究了这些肽与不同磷脂组成的脂质膜的相互作用。两种肽在水性介质中都是无规卷曲的，当将它们掺入DOPC脂质双层时，它们的构型变为α-螺旋。在这个脂膜中 与PEP相比，荧光肽（C-PEP）的膜相互作用与脂质双层中的分配略高。然而，通过与香豆素部分的缀合，脂膜内采用的二级结构没有显着改变。在DPPC：DOPC（50:50）脂质体中，两种肽的分配都较少，这是因为脂质膜的流动性较弱而阻碍了掺入。在细菌模型脂质膜POPE：POPG（70:30）制成的脂质体中，采用聚脯氨酸II（PPII）型结构观察到更大的分配常数。与香豆素部分缀合的结果，较小的构象破坏将允许使用荧光技术对肽与膜的动态相互作用进行建模。