Raman Characterization of Fungal DHN and DOPA Melanin Biosynthesis Pathways.

Fungal melanins represent a resource for important breakthroughs in industry and medicine, but the characterization of their composition, synthesis, and structure is not well understood. Raman spectroscopy is a powerful tool for the elucidation of molecular composition and structure. In this work, we characterize the Raman spectra of wild-type and and their melanin biosynthetic mutants and provide a rough "map" of the DHN () and DOPA () melanin biosynthetic pathways. We compare this map to the Raman spectral data of wild-type and melanin biosynthetic mutants obtained from a previous study. We find that the fully polymerized melanin cannot be classified according to the DOPA pathway; nor can it be solely classified according to the DHN pathway, consistent with mutational analysis and chemical inhibition studies. Our approach points the way forward for an increased understanding of, and methodology for, investigating fungal melanins.