State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, SoutheastUniversity, Nanjing 210096, China.
Molecules. 2017 Aug 12;22(8):1342. doi: 10.3390/molecules22081342.
Nanowires that transfer electrons to extracellular acceptors are important in organic matter degradation and nutrient cycling in the environment. Geobacter pili of the group of Type IV pilus are regarded as nanowire-like biological structures. However, determination of the structure of pili remains challenging due to the insolubility of monomers, presence of surface appendages, heterogeneity of the assembly, and low-resolution of electron microscopy techniques. Our previous study provided a method to predict structures for Type IV pili. In this work, we improved on our previous method using molecular dynamics simulations to optimize structures of Neisseria gonorrhoeae (GC), Neisseria meningitidis and Geobacter uraniireducens pilus. Comparison between the predicted structures for GC and Neisseria meningitidis pilus and their native structures revealed that proposed method could predict Type IV pilus successfully. According to the predicted structures, the structural basis for conductivity in G.uraniireducens pili was attributed to the three N-terminal aromatic amino acids. The aromatics were interspersed within the regions of charged amino acids, which may influence the configuration of the aromatic contacts and the rate of electron transfer. These results will supplement experimental research into the mechanism of long-rang electron transport along pili of electricigens.
将电子转移到细胞外受体的纳米线在有机物降解和环境中养分循环中很重要。属于 IV 型菌毛的丛毛菌被认为是类似纳米线的生物结构。然而，由于单体的不溶性、表面附属物的存在、组装的异质性和电子显微镜技术的低分辨率，确定菌毛的结构仍然具有挑战性。我们之前的研究提供了一种预测 IV 型菌毛结构的方法。在这项工作中，我们使用分子动力学模拟对之前的方法进行了改进，以优化淋病奈瑟菌 (GC)、脑膜炎奈瑟菌和产铀还原杆菌菌毛的结构。GC 和脑膜炎奈瑟菌菌毛的预测结构与其天然结构的比较表明，所提出的方法可以成功预测 IV 型菌毛。根据预测的结构，推测 G.uraniireducens 菌毛中的导电性的结构基础归因于三个 N 端芳香族氨基酸。这些芳香族氨基酸散布在带电荷的氨基酸区域之间，这可能影响芳香族接触的构象和电子转移的速率。这些结果将补充关于沿电生菌菌毛进行长程电子传递机制的实验研究。
