US Patent 7115753 Triaryl cation antibiotics from environmental DNA

Disclosed are triaryl cationic compounds that exhibit broad spectrum antibiotic and antifungal activity, pharmaceutical compositions containing the compounds, and methods of treating bacterial and fungal infections using the compounds. The compounds were initially isolated by screening a 25,000-member bacterial artificial chromosome (BAC) library of environmental (eDNA) from soil. At least one clone produced a dark brown melanin-like compound that was found to have antibiotic activity. The compounds were isolated and synthesized de novo. From within the positive clone, a single open reading frame that shares extensive sequence similarity with members of the 4-hydroxyphenylpyruvate family of enzymes was found to be necessary and sufficient to confer the production of at least one of the subject compounds on E. coli.