Flexible, symmetry-directed approach to assembling protein cages

Significance The ability to organize biological molecules into new hierarchical forms represents an important goal in synthetic biology. However, designing new quaternary interactions between protein subunits has proved technically challenging and has generally required extensive redesign of protein−protein interfaces. Here, we demonstrate a conceptually simple way to assemble a protein into a well-defined geometric structure that uses coiled-coil sequences as “off-the-shelf” components. This approach is inherently modular and adaptable to a wide range of proteins and symmetries, opening up avenues for the construction of biological structures with diverse geometries and wide-ranging functionalities.