5x9j
From Proteopedia
Structure of PrhC from Penicillium brasilianum NBRC 6234
Structural highlights
FunctionPRHC_PENBI Isomerase; 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 PubMedTrt14 from Aspergillus terreus is involved in unusual skeletal reconstruction during the biosynthesis of the fungal meroterpenoid terretonin. Detailed in vitro characterization revealed that this novel multifunctional enzyme catalyzes not only the D-ring expansion via intramolecular methoxy rearrangement, but also the hydrolysis of the expanded D-ring. The X-ray crystal structures of Trt14, in complex with substrate or product, and two Trt14 homologs, AusH and PrhC from Aspergillus nidulans and Penicillium brasilianum, respectively, indicated similar overall structures to those of the NTF2-like superfamily of enzymes, despite lacking sequence and functional similarities. Moreover, we gained structural insight into the mechanism of the Trt14-catalyzed ring reconstruction from the in-crystal enzyme reaction and site-directed mutagenesis to show that this reaction involves sequential ester bond cleavage and formation. Structural comparison of Trt14 and its homologs suggests that the enzymes in this new superfamily employ similar acid-base chemistry to diversify the molecular architecture of fungal meroterpenoids. Molecular basis for the unusual ring reconstruction in fungal meroterpenoid biogenesis.,Mori T, Iwabuchi T, Hoshino S, Wang H, Matsuda Y, Abe I Nat Chem Biol. 2017 Oct;13(10):1066-1073. doi: 10.1038/nchembio.2443. Epub 2017, Jul 31. PMID:28759016[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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