A Broad-Spectrum Copper Oxidase Synthesizes Fungal Peptidomelanin

Area of Science:

• Biochemistry
• Mycology
• Enzymology

Background:

• Peptidomelanin is a fungal biopolymer from Aspergillus niger spores.
• It consists of an L-DOPA derived core and solubilizing peptides.

Purpose of the Study:

• Identify and biochemically characterize the enzyme responsible for peptidomelanin synthesis.
• Elucidate the biochemical pathway involved in fungal melanogenesis.

Main Methods:

• Gene identification and cloning of BroSCO (ABHI18_005222).
• Biochemical assays to determine enzyme activity and substrate specificity.
• Structural modeling of the BroSCO enzyme.

Main Results:

• BroSCO, a broad-spectrum copper oxidase, was identified as the key enzyme.
• BroSCO utilizes the Raper-Mason pathway to polymerize L-DOPA into melanin.
• The enzyme oxidizes thiols from cysteine and peptides, enabling copolymerization for peptidomelanin formation.

Conclusions:

• BroSCO is the enzyme responsible for peptidomelanin biosynthesis.
• A novel biochemical pathway for fungal melanogenesis has been characterized.
• This expands the understanding of fungal biochemistry and melanin production.