Paper NS2-TuA7
Clathrin: A Protein Scaffold for Biotemplating 2-D and 3-D Nanostructures

Tuesday, November 10, 2009, 4:00 pm, Room L

Nature has evolved numerous methods for the self-assembly of nanoscale architectures with high levels of precision. Biomolecules such as DNA, bacterial membranes, viral particles, and proteins all exhibit stunning regularity and reproducibility in the structures they can achieve, making them ideal templates for the patterning of inorganic nanostructures. While some success has been realized in patterning materials from these biological templates, they generally have been limited to simple 0-D or 1-D structures. In contrast, proteins have the ability to form 2-D and 3-D structures, and the immense library of naturally available proteins encourages the development of new techniques to reproducibly template these materials.

Using clathrin as a model protein, we are developing flexible biotemplating protocols to interface protein structures with a variety of inorganic materials. The intracellular transport protein clathrin is composed of three semi-flexible arms that form a pinwheel structure with three-fold symmetry. Clathrin provides a framework that offers access to a variety of architectures, both 2-D and 3-D, such as sheets, tetragons, and geodesic spheres depending on the environmental conditions (pH, concentration, buffer ionic strength) during assembly. The ability of this single protein to assemble into multiple structures makes clathrin an ideal model system for investigating the underlying kinetic and thermodynamic principles of self-assembly. To interface these biological templates with inorganic materials, we design bi-functional peptide linkers that serve as molecular bridges between the clathrin protein and inorganic materials. Rational design of these bi-functional peptide linkers includes a conserved clathrin-binding motif fused to an inorganic-binding peptide sequence. This newly developed strategy enables great flexibility to interface a single protein biotemplate with a variety of different inorganics without requiring any direct modifications to the template. The ability of a single protein biotemplate to assemble into multiple 2-D and 3-D protein nanostructures and to interface with a variety of inorganic materials makes this modular, self- assembling system applicable to a broad range of applications.