Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.
J Phys Chem B. 2013 Aug 22;117(33):9690-8. doi: 10.1021/jp4059752. Epub 2013 Aug 8.
Amphiphilic peptides are receiving considerable interest for drug delivery because of their self-assembly nature. A molecular dynamics simulation study is reported here to investigate the self-assembly of FA32 peptide composed of 32 amino acid (AF)6H5K15. The peptide, as well as water and counterions, are represented by the MARTINI coarse-grained model. Within 5 μs simulation duration, the peptide is observed to form micelles. Ala and Phe stay in the hydrophobic core, Lys in the hydrophilic shell, and amphiphilic His at the interface. The assembly process and microscopic structures are analyzed in terms of the number of clusters, the radii of micelle, core and shell, and the density profiles of residues. A three-step process is proposed for the assembly: small clusters are initially aggregated and then merged into large clusters, eventually micelles are formed. The effects of simulation box size and peptide concentration are examined in detail. It is found that the micellar structures and microscopic properties are essentially independent of box size. With increasing concentration, quasi-spherical micelles change to elongated shape and micelle size generally increases. The simulation study provides microscopic insight into the assembly process of FA32 peptide and the microscopic structures.
两亲性肽因其自组装性质而受到药物输送的广泛关注。本文报道了一项分子动力学模拟研究，以研究由 32 个氨基酸（AF）6H5K15 组成的 FA32 肽的自组装。该肽以及水和抗衡离子均采用 MARTINI 粗粒度模型表示。在 5 μs 的模拟时间内，观察到肽形成胶束。Ala 和 Phe 留在疏水区，Lys 在亲水区，两亲 His 在界面处。通过簇的数量、胶束、核心和壳的半径以及残基的密度分布来分析组装过程和微观结构。提出了一个三步组装过程：小簇最初聚集，然后合并成大簇，最终形成胶束。详细研究了模拟盒尺寸和肽浓度的影响。结果发现，胶束结构和微观性质基本与盒尺寸无关。随着浓度的增加，准球形胶束变为拉长形状，胶束尺寸通常增大。模拟研究提供了 FA32 肽组装过程和微观结构的微观见解。
