Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany.
Faraday Discuss. 2018 Sep 28;209(0):341-358. doi: 10.1039/c8fd00011e.
Artificial channels made of carbon nanotube (CNT) porins are promising candidates for applications in filtration and molecular delivery devices. Their symmetric shape and high mechanical, chemical, and thermal stability ensure well-defined transport properties, and at the same time make them ideal model systems for more complicated membrane protein pores. As the technology to produce and tune CNTs advances, simulations can aid in the design of customized membrane porins. Here we concentrate on CNTs embedded in lipid membranes. To derive design guidelines, we systematically studied the interaction of CNT porins with their surrounding lipids. For our simulations, we developed an AMBER- and Lipid14-compatible parameterization scheme for CNTs with different chirality and with functional groups attached to their rim, and a flexible coarse-grained description for open-ended CNTs fitting to the MARTINI lipid model. We found that the interaction with lipid acyl chains is independent of the CNT chirality and the chemical details of functional groups at the CNT rims. The latter, however, are important for the interactions with lipid head groups, and for water permeability. The orientation and permeability of the pore are mainly determined by how well its hydrophobicity pattern matches the membrane. By identifying the factors that determine the structure both of isolated CNTs in lipid membranes and of CNT clusters, we set the foundation for a targeted design of CNT-membrane systems.
人工碳纳米管（CNT）通道是过滤和分子输送装置应用的有前途的候选物。它们的对称形状和高机械、化学和热稳定性确保了明确的传输特性，同时使它们成为更复杂的膜蛋白孔的理想模型系统。随着生产和调整 CNT 的技术的进步，模拟可以帮助设计定制的膜孔道。在这里，我们专注于嵌入脂质膜的 CNT。为了得出设计准则，我们系统地研究了 CNT 通道与周围脂质的相互作用。对于我们的模拟，我们为具有不同手性和边缘带有官能团的 CNT 开发了一种与 AMBER 和 Lipid14 兼容的参数化方案，以及一种适用于开放式 CNT 的灵活的粗粒度描述，适用于 MARTINI 脂质模型。我们发现，与脂质酰基链的相互作用与 CNT 的手性和 CNT 边缘官能团的化学细节无关。然而，后者对于与脂质头基团的相互作用以及水渗透性很重要。孔的取向和渗透性主要取决于其疏水性模式与膜的匹配程度。通过确定决定脂质膜中孤立 CNT 结构和 CNT 簇结构的因素，我们为有针对性地设计 CNT-膜系统奠定了基础。
