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

Abstract

Mycophenolic acid (MPA, 1) 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 1, especially the processes involving the cleavage of the prenyl side chain between DHMP (4) and DMMPA (5), remains unknown. In this work, we identified a membrane-bound prenyltransferase, PgMpaA, that transfers FPP to 4 to yield FDHMP (6). Compound 6 undergoes the first cleavage step via a new globin-like enzyme PgMpaB to form a cryptic intermediate 12. Heterologous expression of PgMpa genes in Aspergillus nidulans demonstrates that the second cleavage step (from 12 to 5) of 1 is a PgMpa cluster-independent process in vivo. 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.

Discovery of a Dual Function Cytochrome P450 that Catalyzes Enyne Formation in Cyclohexanoid Terpenoid Biosynthesis

“…AtyB contains the same conserved domain as PFAM01040 UbiA prenyltransferases, which usually function as oligoprenyltransferases. [16] A phylogenetic analysis showed that AtyB and its homologues formed a separate clade from other UbiA oligoprenyltransferases, such as MpaA [21] (transfers GPP and FPP) and AscA [22] (transfers FPP) (see Figure S5). Thus, AtyB is an unusual UbiA prenyltransferase that installs a short (C 5 ) prenyl chain to 4.…”

A Fungal Promiscuous UbiA Prenyltransferase Expands the Structural Diversity of Chrodrimanin-Type Meroterpenoids

“…Highperformance liquid chromatography−ultraviolet-mass spectrometry (LC-UV-MS) analysis showed the products with molecular formulas corresponding to a series of benzopyranone-derived chrodrimanins, including chodrimanins A and C; however, no cyclohexanone-type chrodrimanins (such as 1 and 2) were detected (Figure S5). To learn if there were some unclustered enzymes in P. f uniculosum GWT2−24 that were able to catalyze conversion of pyranone-type chrodrimanins into cyclohexanone-type ones, we grew the strain AN-CdnABCDEFGJ on a medium nourished with acetate-1- 13 C and purified the 13 C -abeled chrodrimanin C from the crude extract. The crude extract and pure 13 C-labeled chrodrimanin C were then fed back individually to the wild type GWT2−24.…”

“…To learn if there were some unclustered enzymes in P. f uniculosum GWT2−24 that were able to catalyze conversion of pyranone-type chrodrimanins into cyclohexanone-type ones, we grew the strain AN-CdnABCDEFGJ on a medium nourished with acetate-1- 13 C and purified the 13 C -abeled chrodrimanin C from the crude extract. The crude extract and pure 13 C-labeled chrodrimanin C were then fed back individually to the wild type GWT2−24.…”

“…However, no 13 C-nourished cyclohexanone-type products were detected (Figure S6), which indicated that 1 and 2 were not likely to be converted from the pyranone-type structures. In contrast, they are most likely derived from the farnesylation of a benzocyclohexanone precursor such as the DHN−melanin (DM) analogues catalyzed by the UbiA-type PTase CdnC, which shows substrate promiscuity on diverse polyketide precursors.…”

“…Based on the phylogenetic tree for CdnC and the sequence similarity network (SSN), we found CdnC clustered in a small clade with several classical UbiA-type PTases containing CdmH and MapA, 13 confirming the farnesyl transferase function, while the other UbiA-PTases only showed singlesubstrate selectivity (Figures 4B and S16). A homologous gene cluster-directed search revealed only one strain, Talaromyces amestolkiae CIB, that possessed the complete cdn cluster, which denoted the rare biosynthetic capacity of P. f uniculosum GWT2−24 (Figure S4).…”