Immunosuppressant mycophenolic acid biosynthesis employs a new globin-like enzyme for prenyl side chain cleavage

ABSTRACT

Mycophenolic acid (MPA, ) and its derivatives are first-line immunosuppressants used in organ transplantation and for treating autoimmune diseases. Despite chemical synthetic achievements, the biosynthetic formation of a seven-carbon carboxylic acid pharmacophore side chain of , especially the processes involving the cleavage of the prenyl side chain between DHMP () and DMMPA (), remains unknown. In this work, we identified a membrane-bound prenyltransferase, PgMpaA, that transfers FPP to to yield FDHMP (). Compound undergoes the first cleavage step a new globin-like enzyme PgMpaB to form a cryptic intermediate . Heterologous expression of genes in demonstrates that the second cleavage step (from to ) of is a cluster-independent process . Our results, especially the discovery of the broad tolerance of substrates recognized by PgMpaB, set up a strategy for the formation of "pseudo-isopentenyl" natural products using fungal globin-like enzymes.