Researchers of the Institute of Biotechnology and Biomedicine at the Universitat Autònoma de Barcelona, (IBB-UAB), Spain, have achieved the generation of four peptides capable of self-assembling in a controlled manner, creating nanomaterials.
The research into creating nanomaterials was conducted by Salvador Ventura, Marta Díaz and Susanna Navarro (IBB-UAB), and included the collaboration of Isabel Fuentes and Francesc Teixidor (Institute of Materials Science of Barcelona (ICMAB-CSIC).
The new molecules are formed by a chain of seven amino acids, each of which are made up of two different amino acids, meaning that they significantly speed up and reduce the price of the process of the creation of functional synthetic amyloid structures, which are used to create nanomaterials with applications in biomedicine and nanotechnology.
Generating synthetic amyloid structures
According to the university, generating functional synthetic amyloid structures to form nanostructures by imitating the natural generation process is nothing new. The assembly of proteins into stable fibres allows creating supramolecular shapes which no isolated protein can create, and which are used as nanoconductors, photovoltaic structures, biosensors and catalysts.
Quite recently, prion protein sequences – also amyloids – began to be imitated to create nanomaterials. The interest in these sequences surrounds the fact that the proteins assemble in a slower and more controlled manner, forming highly ordered non-toxic nanostructures. However, the fact that the sequence is so long, with over 150 amino acids, makes it very difficult and expensive to synthesise.
Ventura said: “We have demonstrated that an adequate design can permit the size of synthetic prion sequences to be reduced down to only seven amino acids, while conserving the same properties. The four peptides we have fabricated are the shortest structures of this type created until now and capable of forming stable fibril assemblies.”
What did the study demonstrate?
In the study, the researchers verified the stability and functionality of the four fabricated peptides, building one of the most degradation-resistant biological nanomaterials described to date. These were nanocables covered in silver which can act as electrical nanoconductors and fibrillar mini enzymes capable of acting as catalysts in the formation of organic nanomaterials.
Ventura said: “The final objective will be to generate hybrid peptide-inorganic materials capable of making complex reactions, as those created by the photosystems of plants”
In order to generate new peptides, the researchers based their work on specific sequences of prion proteins, known as prion domains (PrDs).
Ventura explained: “We studied which amino acids are more frequent and how they are distributed in these regions, demonstrating that only four different types of amino acids distributed in a specific manner and always combined by a fifth type of amino acid is sufficient to have the complete code needed to form synthetic prion fibres.”
This study has helped researchers of the IBB Protein Folding and Conformational Diseases group, directed by Ventura, to open a new line of research focused on creating nanomaterials.