As an alternative to antibiotics, Antimicrobial Peptides (AMPs) possess unique properties including cationic, amphipathic and their abundance in nature, but the exact characteristics of AMPs against bacterial membranes are still undetermined. To estimate the structural stability and functional activity of AMPs, the Pseudin AMPs (Pse-1, Pse-2, Pse-3, and Pse-4) from Hylid frog species, Pseudis paradoxa, an abundantly discovered source for AMPs were examined. We studied the intra-peptide interactions and thermal denaturation stability of peptides, as well as the geometrical parameters and secondary structure profiles of their conformational trajectories. On this basis, the peptides were screened out and the highly stable peptide, Pse-4 was subjected to membrane simulation in order to observe the changes in membrane curvature formed by Pse-4 insertion. Monomeric Pse-4 was found to initiate the membrane disruption; however, a stable multimeric form of Pse-4 might be competent to counterbalance the helix-coil transition and to resist the hydrophobic membrane environment. Eventually, hexameric Pse-4 on membrane simulation exhibited the hydrogen bond formation with E. coli bacterial membrane and thereby, leading to the formation of membrane spanning pore that allowed the entry of excess water molecules into the membrane shell, thus causing membrane deformation. Our report points out the mechanism of Pse-4 peptide against the bacterial membrane for the first time. Relatively, Pse-4 works on the barrel stave model against E. coli bacterial membrane; hence it might act as a good therapeutic scaffold in the treatment of multi-drug resistant bacterial strains.

作为抗生素的替代品，抗菌肽（AMP）具有独特的性质，包括阳离子、两亲性及其在自然界中的丰富性，但 AMP 对抗细菌膜的确切特性仍待确定。为了评估 AMP 的结构稳定性和功能活性，对来自青蛙种 Pseudis paradoxa 的 Pseudin AMP（Pse-1、Pse-2、Pse-3 和 Pse-4）进行了检查，Pseudis paradoxa 是一种被发现的丰富的 AMP来源。我们研究了肽内的相互作用和肽的热变性稳定性，以及其构象轨迹的几何参数和二级结构特征。在此基础上筛选出肽段，并对高度稳定的肽段Pse-4进行膜模拟，以观察Pse-4插入后形成的膜曲率的变化。发现单体 Pse-4 会引发膜破坏；然而，Pse-4 的稳定多聚体形式可能能够平衡螺旋-螺旋转变并抵抗疏水性膜环境。最终，膜模拟上的六聚体Pse-4表现出与大肠杆菌细菌膜形成氢键，从而导致跨膜孔的形成，使多余的水分子进入膜壳，从而导致膜变形。我们的报告首次指出了Pse-4肽对抗细菌膜的作用机制。相对而言，Pse-4在桶板模型上作用于大肠杆菌细菌膜；因此，它可能作为治疗多重耐药菌株的良好治疗支架。