Assembly of multimeric phage nanostructures through leucine zipper interactions.

One barrier to the construction of nanoscale devices is the ability to place materials into 2D- and 3D-ordered arrays by controlling the assembly and ordering of connections between nanomaterials. Ordered assembly of nanoscale materials may potentially be achieved using biological tools that direct specific connections between individual components. Recently, viruses were successfully employed as scaffolds for the nucleation of nanoparticles and nanowires (Mao et al., 2004); however, there is a paucity of methods for the higher order assembly of phage-templated materials. Here we describe a general strategy for the assembly of filamentous bacteriophages into long, wire-like or into tripod-like structures. To prepare the linear phage assemblies, dimeric leucine zipper protein domains, fused to the p3 and p9 proteins of M13 bacteriophage, were employed to direct the specific end-to-end self-association of the bacteriophage particles. Electron microscopy revealed that up to 90% of the phage displaying complementary leucine zipper domains formed linear multi-phage assemblies, composed of up to 30 phage in length. To prepare tripod-like assemblies, phage were engineered to express trimeric leucine zippers as p3 fusion proteins. This resulted in 3D assembly with three individual phages attached at a single point. These ordered phage structures should provide a foundation for self-assembly of virally templated nanomaterials into useful devices.