5ybo
Fe(II)/(alpha)ketoglutarate-dependent dioxygenase PrhA in complex with preaustinoid A1
Structural highlights
FunctionPRHA_PENBI Multifunctional dioxygenase; part of the gene cluster that mediates the biosynthesis of paraherquonin, a meroterpenoid with a unique, highly congested hexacyclic molecular architecture (PubMed:27602587). The first step of the pathway is the synthesis of 3,5-dimethylorsellinic acid (DMOA) by the polyketide synthase prhL (By similarity). Synthesis of DMOA is followed by farnesylation by the prenyltransferase prhE, methylesterification by the methyl-transferase prhM, epoxidation of the prenyl chain by the flavin-dependent monooxygenase prhF, and cyclization of the farnesyl moiety by the terpene cyclase prhH, to yield the tetracyclic intermediate, protoaustinoid A (By similarity). The short chain dehydrogenase prhI then oxidizes the C-3 alcohol group of the terpene cyclase product to transform protoaustinoid A into protoaustinoid B (PubMed:27602587). The FAD-binding monooxygenase prhJ catalyzes the oxidation of protoaustinoid B into preaustinoid A which is further oxidized into preaustinoid A1 by FAD-binding monooxygenase phrK (PubMed:27602587). Finally, prhA leads to berkeleydione via the berkeleyone B intermediate (PubMed:27602587, PubMed:29317628). PrhA is a multifunctional dioxygenase that first desaturates at C5-C6 to form berkeleyone B, followed by rearrangement of the A/B-ring to form the cycloheptadiene moiety in berkeleydione (PubMed:27602587, PubMed:29317628). Berkeleydione serves as the key intermediate for the biosynthesis of paraherquonin as well as many other meroterpenoids (Probable). The cytochrome P450 monooxygenases prhB, prhD, and prhN, as well as the isomerase prhC, are probably involved in the late stage of paraherquonin biosynthesis, after the production of berkeleydione (Probable). Especially prhC might be a multifunctional enzyme that catalyzes the D-ring expansion via intramolecular methoxy rearrangement, as well as the hydrolysis of the expanded D-ring (Probable).[UniProtKB:Q5ATJ7][1] [2] [3] [4] [5] Publication Abstract from PubMedNon-heme iron and alpha-ketoglutarate (alphaKG) oxygenases catalyze remarkably diverse reactions using a single ferrous ion cofactor. A major challenge in studying this versatile family of enzymes is to understand their structure-function relationship. AusE from Aspergillus nidulans and PrhA from Penicillium brasilianum are two highly homologous Fe(II)/alphaKG oxygenases in fungal meroterpenoid biosynthetic pathways that use preaustinoid A1 as a common substrate to catalyze divergent rearrangement reactions to form the spiro-lactone in austinol and cycloheptadiene moiety in paraherquonin, respectively. Herein, we report the comparative structural study of AusE and PrhA, which led to the identification of three key active site residues that control their reactivity. Structure-guided mutagenesis of these residues results in successful interconversion of AusE and PrhA functions as well as generation of the PrhA double and triple mutants with expanded catalytic repertoire. Manipulation of the multifunctional Fe(II)/alphaKG oxygenases thus provides an excellent platform for the future development of biocatalysts. Structure function and engineering of multifunctional non-heme iron dependent oxygenases in fungal meroterpenoid biosynthesis.,Nakashima Y, Mori T, Nakamura H, Awakawa T, Hoshino S, Senda M, Senda T, Abe I Nat Commun. 2018 Jan 9;9(1):104. doi: 10.1038/s41467-017-02371-w. PMID:29317628[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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