As engineering focuses attention on controlling and manipulating nano-scale materials and processes, a role for biomolecules, like proteins, is emerging to address the fundamental problems associated with working at the nanometer-size scale.  Proteins can be readily modified using genetic engineering and induced to interact with a surprising range of organic and inorganic materials.  We are using genetic engineering to modify proteins from extremophiles to bind metals and semi-conducting materials and to direct or redirect the inherent properties of these proteins to self-assemble into useful nanostructures. In particular, I will describe our use of the genetically engineered 60-kDa heat shock proteins (HSP60s) from Sulfolobus shibatae, which naturally self-assemble into robust double-ring structures, called “rosettasomes.” We have manipulated rosettasomes to use them as templates for arranging nanoparticles in arrays with nanometer precision.  I will discuss how these arrays can be used for applications in data storage on computer hard drives.