S142: Rare actinomycetes genome mining for cryptic polyene macrolide and novel cytochrome P450 hydroxylase

Using a polyene macrolide specific genome mining strategy, a rare actinomycetes Pseudonocardia autotrophica was determined to contain an 125.7 kb region of contiguous DNA with a total of 23 open reading frames, which are involved in the biosynthesis of a cryptic polyene natural product named Nystatin-like Pseudonocardia Polyene (NPP). The complete structure of NPP was determined to contain an aglycone identical to nystatin and to harbor a unique di-sugar moiety, mycosaminyl-(α1-4)-N-acetyl-glucosamine. Compared with nystatin, this di-sugar containing NPP exhibits approximately 300-fold higher water solubility and 10-fold reduced hemolytic activity, while retaining about 50% antifungal activity against Candida albicans. These characteristics reveal NPP as a promising candidate for further development into a pharmacokinetically improved, less-cytotoxic polyene antifungal antibiotic.

Regio-specific hydroxylation of an immunosuppressive Cyclosporin A (CsA) has been proposed to be the reason for maintaining the hair growth-promoting side effect without the immunosuppressive activity of CsA. Through rare actinomycetes Sebekia benihana genome sequencing and in silico analysis, the complete cytochrome P450 hydroxylase complements (CYPome) were identified. Using CYPome-targeted gene disruption, all of the 32 identified CYPome genes in S. benihana were individually inactivated, and only single S. benihana CYPome mutant failed to exhibit CsA-specific hydroxylation activity. These results show that regio-specific hydroxylation of CsA is carried out by a specific P450 hydroxylase present in S. benihana.