IDEA #79TJBK Self-Assembling Peptide Melanines.AUSTRALIAN patent application #2017360269 filed 20170911.

Melanin pigments are found in most living forms, from plants to bacteria to fungi and animals, where they have cardinal roles in organisms' coloration and protection from various cell damage causing stresses. In addition to their protecting roles, the remarkable functionality of melanin pigments includes p hoto protection, free radical scavenging and electronic properties The self assembly and polymerization of natural melanin is regulated through a complex process involving catalysis, assembly, confinement and compartmentalization that is currently poorly understood. The formation of synthetic melanin occurs through uncontrolled oxidation of tyrosine residues and subsequent polymerization yielding highly insoluble polymers with poorly defined chemical and structural components, limiting the materials’ usability. Thus, there is a need for enhanced control of synthetic melanin's processing while maintaining and ultimately tuning its functionality. We offer to control the oxidation and polymerization of tyrosine into melanin like materials by presenting the tyrosine residues with nanoscale precision in a sterically and chemically tunable micro environment. The first step of melanin formation consists of the oxidation of the amino acid tyrosine to a range of catechols, which subsequently undergo a series of oxidation and polymerization steps to form melanin. Thus, supramolecular materials formed by self assembly of tyrosine containing short peptides provide an attractive potential solution to this challenge. Supramolecular materials formed by peptide or protein building blocks offer considerable promise in this context due to the ability to precisely control the presentation of chemical functionality (and consequently, reactivity) in 3D space through non covalent interactions. Even very short peptides, consisting of only two or three amino acids have been shown to self assemble to form discrete nanoscale materials with tunable optical, mechanical, electrical and piezoelectric properties, as well as active materials driven by chemical fuel consumption . Furthermore, combining short peptide self assembly with (bio --) catalytic transformations of key residues provides spatiotemporal control over the assembly process, giving rise to tunable properties. Thus, (catalytic) self assembly of short peptides offers an attractive approach for materials design due to their simplicity, tunability and low cost manufacturing. Here we report that supramolecular order in tyrosine tri peptides can template the formation of materials with functional melanin properties with unprecedented tunability through pathway control. In this approach, peptide sequence dictates the supramolecular organization that provides tunable steric microenvironment of tyrosine residues, leading to a controlled enzymatic oxidation and polymerization pathway.