Surfaces functionalized with self-assembling S-layer fusion proteins for nanobiotechnological applications

Abstract

The fabrication of supramolecular structures and devices requires molecules that are capable of interlocking in a predictable well defined manner on surfaces required for nanobiotechnological applications. Thus, molecular self-assembly systems which exploit the molecular scale manufacturing precision of biological systems are prime candidates for supramolecular engineering. In this context, crystalline bacterial cell surface layer (S-layer) proteins of prokaryotic organisms represent a unique self-assembly system which can be exploited as patterning element for a biomolecular construction kit involving all major species of biological molecules, for example, glycans such as S-layer-specific heteropolysaccharides, lipids, and nucleic acids. One of the most fascinating properties of native or recombinant S-layer proteins is their capability to self-assemble in suspension (as flat sheets or cylinders), into monomolecular protein lattices on artificial surfaces (e.g. silicon wafers, noble metals, plastics) or on Langmuir lipid films and liposomes. Functional groups (e.g. carboxyl groups, amino or hydroxyl groups) or genetically incorporated functional domains (e.g. streptavidin) are repeated with the periodicity of the S-layer lattice at a distance resembling the lattice constants, leading to regular arrays of bound functional molecules or nanoparticles. Thus, genetically and/or chemically modified S-layer proteins can be exploited as building blocks and templates for generating functional nanostructures at meso- and macroscopic scale for both, life and non-life science applications.