Protein engineering is an attractive approach for the self-assembly of nanometer-scale architectures for a range of potential nanotechnologies. Using the versatile chemistry provided by protein folding and assembly, coupled with amino acid side-chain functionality, allows for the construction of precise molecular “protein origami” hierarchical patterned structures for a range of nanoapplications such as stand-alone enzymatic pathways and molecular machines. The Staphyloccocus aureus surface protein SasG is a rigid, rod-like structure shown to have high mechanical strength due to “clamp-like” intradomain features and a stabilizing interface between the G5 and E domains, making it an excellent building block for molecular self-assembly. Here we characterize a new two subunit system composed of the SasG rod protein genetically conjugated with de novo designed coiled-coils, resulting in the self-assembly of fibrils. Circular dichroism (CD) and quartz-crystal microbalance with dissipation (QCM-D) are used to show the specific, alternating binding between the two subunits. Furthermore, we use atomic force microscopy (AFM) to study the extent of subunit polymerization in a liquid environment, demonstrating self-assembly culminating in the formation of linear macromolecular fibrils.

中文翻译：

---

螺旋线圈连接的SasG蛋白原纤维的合理设计和自组装。

对于一系列潜在的纳米技术，蛋白质工程是一种用于纳米级结构自组装的有吸引力的方法。使用蛋白质折叠和组装提供的多功能化学方法，再加上氨基酸侧链功能，可以构建精确的分子“蛋白质折纸”层次结构化的结构，以用于一系列纳米应用，例如独立的酶促途径和分子机器。在金黄色葡萄球菌表面蛋白SasG是一种刚性的杆状结构，由于“钳形”结构域内特征以及G5和E结构域之间的稳定界面而具有较高的机械强度，使其成为分子自组装的极佳构建基块。在这里，我们表征了由SasG杆蛋白组成的新的两个亚基系统，该蛋白与从头设计的卷曲螺旋基因共轭，导致原纤维的自组装。圆二色性（CD）和带耗散的石英晶体微天平（QCM-D）用于显示两个亚基之间特定的交替结合。此外，我们使用原子力显微镜（AFM）来研究液体环境中亚基的聚合程度，证明自组装最终形成线性大分子原纤维。