This chapter will focus on the description of protein-based nanostructures. How proteins can be used as molecular units in order to generate complex materials and structures? What are the key aspects to achieve defined final properties, including shape, stability, function, and order at different length scales by modifying the protein sequence at the modular level?As described in other chapters of the book, we will review the basic concepts and the latest achievements in protein engineering toward nanotechnological applications. Particularly in this chapter the main focus will be on a particular type of proteins, repeat proteins. Because of their modular nature, these proteins are better suited to be used as building blocks than other protein scaffolds. First, we describe general concepts of the protein-based assemblies. Then we introduce repeat proteins and describe the properties that will impact their use in nanotechnology. In particular, we focus on a system based on a synthetic protein, the consensus tetratricopeptide repeat (CTPR). We review recent works from other groups and our group in which the potential of these repeat protein scaffolds is exploited for the fabrication of different protein assemblies, and as biomolecular templates to arrange different molecules and nanoscale objects.
Keywords: Biomaterials; Biomolecular scaffolds; Bionanotechnology; Designed proteins; Functional materials; Hybrid structures; Nanoclusters; Nanoparticles; Nanostructures; Repeat proteins; Self-assembly.