Many animals use molecular crystals for an astonishing variety of optical functions, from vision to the production of structural colors in fish and chameleons. These intracellular molecular crystals play vital roles in the function of cells and the ecology of different organisms. Thus, failure of the mechanisms controlling crystal formation can be highly deleterious to the organism and may result in pathologies, such as gout and kidney stones in humans.
The orchestrated precipitation of organic materials, which produces crystals with unique morphologies and properties at ambient conditions, occurs within specialized crystal-forming cells, such as the light-reflecting iridophores. Inside iridophores, guanine crystals develop in an organelle dubbed iridosome, where exquisite control over crystal size, shape and assembly is exerted using strategies exceeding the synthetic state-of-the-art. Understanding the capacity of cells to generate a compartmentalized organelle capable of such intricate chemical and biological processes has thus far been limited by the technical inability to study this complex organelle, thus representing an underexplored avenue in cell biology.
Crystal formation involves a sequence of events that predominately occurs early in the life cycle of the iridophore. It starts with the synthesis and trafficking of vast quantities of precursor molecules into the iridosome, followed by their concentration within the iridosome lumen and, ultimately, culminating in the formation of bio-organic crystals with controlled properties. The resulting product, a precisely shaped and sized crystal, is then placed within ordered crystal arrays, which are often tunable. The mechanisms underlying the molecular and cellular biology of the iridosome have remained largely unknown, leaving many important unresolved questions: How are iridosomes formed? Which machinery is involved in the crystal formation process? How conserved are these processes between different species? This project is focused on answering these fundamental questions using an interdisciplinary set of skills, merging chemistry, crystallography, and cell biology. For that, we have developed new approaches and applied methodologies that have sufficiently matured in recent years. Our ultimate goal is to provide a mechanistic understating of the processes and principles governing the controlled formation of molecular crystals.
