Pradeep, P. | Search bioRxiv

bioRxiv2026

Characterization of a novel soluble melanin secreted by Gliomastix polychroma

Melanin is a heterogeneous, amorphous biopolymer widely distributed in biological systems, yet most canonical forms are intrinsically insoluble. Soluble melanins are rare and remain poorly characterized, with pyomelanin and peptidomelanin representing the best-described fungal examples. Here, we report the isolation and characterization of a distinct, polyphyletic class of soluble melanin that we term `colloidal melanin'. This class of polymers was isolated from four different species of Ascomycetous fungi occupying varied environmental niches. Colloidal melanin was found to be phenolic and nitrogenous, with a low amino acid content. The polymers form particles with median diameters ranging from 79 to 127 nm, suggesting that small particle size may contribute to aqueous solubility via colloidal dispersion. Using chemical inhibition of melanin biosynthesis together with whole-genome sequencing, we show that colloidal melanin can be produced through multiple distinct biochemical pathways. Further, genes identified as involved in melanin biosynthesis across species do not share any detectable common ancestry, consistent with convergent evolution. Together, these findings identify a distinct class of soluble melanin that does not conform to existing soluble melanin classifications.

biochemistry↗

bioRxiv2024

Arktos: a simple tool for the design of polyhedral 1DNA nanostructures

DNA nanostructures are a class of self-assembling nanomaterials with a wide range of potential applications in biomedicine and nanotechnology. The history of DNA nanotechnology can be traced back to the 1980s with the development of simple DNA polyhedra using either human intuition or simple algorithms. Today the field is dominated by DNA origami constructs to such an extent that the original algorithms used to design non-origami nanostructures have been lost. In this work we describe Arktos: an algorithm developed to design simple DNA polyhedra without the use of DNA origami. Arktos designs sequences predicted to fold into a desired structure using simulated annealing optimization. As a proof-of-concept, we used Arktos to design a simple DNA tetrahedron. The generated oligonucleotide sequences were synthesized and experimentally validated via polyacrylamide gel electrophoresis, indicating that they fold into the desired structure. These results demonstrate that Arktos can be used to design custom DNA polyhedra as per the needs of the research community.

bioinformatics↗