Bacterial colonization of abiotic surfaces such as those of medical implants, membrane filters, and everyday household items is a process of tremendous importance for public health. Bacteria use adhesive cell surface structures called adhesins to establish contact with abiotic surfaces. Among them, protein filaments called type IV pili are particularly important and found in many Gram-negative pathogens such as Pseudomonas aeruginosa. Understanding the interaction of such adhesin proteins with different abiotic surfaces at the molecular level thus represents a fundamental prerequisite for impeding bacterial colonization and preventing the spread of infectious diseases. In this work, we investigate the interaction of a synthetic adhesin-like peptide, PAK128-144ox, derived from the type IV pilus of P. aeruginosa with hydrophilic and hydrophobic self-assembled monolayers (SAMs). Using a combination of molecular dynamics (MD) simulations, quartz crystal microbalance with dissipation monitoring (QCM-D), and spectroscopic investigations, we find that PAK128-144ox has a higher affinity for hydrophobic than for hydrophilic surfaces. Additionally, PAK128-144ox adsorption on the hydrophobic SAM is furthermore accompanied by a strong increase in α-helix content. Our results show a clear influence of surface hydrophobicity and further indicate that PAK128-144ox adsorption on the hydrophobic surface is enthalpically favored, while on the hydrophilic surface, entropic contributions are more significant. However, our spectroscopic investigations also suggest aggregation of the peptide under the employed experimental conditions, which is not considered in the MD simulations and should be addressed in more detail in future studies.

中文翻译：

---

表面疏水性对菌毛衍生粘附素样肽吸附的影响

非生物表面（如医疗植入物、膜过滤器和日常家居用品）的细菌定植是一个对公共卫生极为重要的过程。细菌使用称为粘附素的粘附细胞表面结构与非生物表面建立接触。其中，称为IV型菌毛的蛋白丝尤为重要，在许多革兰氏阴性病原体如铜绿假单胞菌中都有发现。因此，在分子水平上了解这些粘附蛋白与不同非生物表面的相互作用是阻止细菌定植和防止传染病传播的基本前提。在这项工作中，我们研究了一种合成的粘附素样肽 PAK128-144ox 的相互作用，该肽来源于 IV 型菌毛。铜绿假单胞菌具有亲水性和疏水性自组装单分子层（SAMs）。结合分子动力学 (MD) 模拟、带耗散监测的石英晶体微天平 (QCM-D) 和光谱研究，我们发现 PAK128-144ox 对疏水表面的亲和力高于对亲水表面的亲和力。此外，疏水 SAM 上的 PAK128-144ox 吸附还伴随着 α-螺旋含量的强烈增加。我们的结果表明表面疏水性的明显影响，并进一步表明 PAK128-144ox 在疏水表面的吸附是焓有利的，而在亲水表面，熵的贡献更显着。然而，我们的光谱研究也表明在所采用的实验条件下肽的聚集，