Molecular recognition unveiled
Many biotechnological applications utilise composite materials where proteins interact with inorganic materials. A prime example is the combination of collagen and hydroxyapatite in biomimetic scaffolds that serve as a mechanical and supportive matrix for the formation of bone. Peptides are also incorporated in nano-structured materials with novel properties and functions for surface biocompatibility and drug delivery. As a result, understanding how proteins interact with inorganic materials should help design effective biomedical materials for a variety of applications. In this context, the EU-funded 'Molecular recognition: Understanding proteins adsorption to inorganic surfaces' (PROADS) project set out to investigate the binding of amino acids onto inorganic substrates. For this purpose, the consortium established a single molecule force spectroscopy using atomic force microscopy to examine how amino acids with different properties interact with inorganic materials in solution. This method is unique in providing information about peptide-inorganic surface interaction at the molecular level with great detail. Researchers determined the strength of interactions between the individual amino acid residues and the inorganic substrate, and also observed how this is influenced by the ionic strength of the solution. They found that hydrophobic and electrostatic interactions are the strongest bonds of peptides attaching onto a silicon substrate and mica. These data were supported by computer simulations that also showed that the binding of the peptide to the substrate is controlled by the relative conformational freedom of the peptide and the substrate in solution. Restricting the movement of the substrate seems to improve the binding efficacy of the peptide. Taken together, PROADS observations have important ramifications for the design of new composite materials. The generated technology could be used further to study the interaction of other molecules and advance biomedical applications.
Keywords
Molecular recognition, peptides, composite materials, adsorption, inorganic surfaces
