Biaryl-Forming Enzymes from Aspergilli Exhibit Substrate-Dependent Stereoselectivity

Obermaier, Sebastian; Müller, Michael

doi:10.1021/acs.biochem.9b00291

Cited by 27 publications

(31 citation statements)

References 28 publications

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“…Moreover, VioM (44.6–50.9 % SeqID) and VirM (44.3–45.2 % SeqID) are sequence homologues of AurJ from the BGC of aurofusarin, which catalyzes O‐methylation of monomeric norrubrofusarin to rubrofusarin ( 9 ) with the same regiochemistry as that of SpoM . A comparable sequence similarity (52.9–57.4 %) is evident in a comparison of VioM and VirM with the O‐MT AunD, which is involved in the biosynthesis of aurasperone B in A. niger to methylate fonsecin to give fonsecin B ( 10 ) . Again, AunD shows the same regioselectivity as that expected for VioM and VirM.…”

Section: Methodssupporting

confidence: 84%

“…Again, AunD shows the same regioselectivity as that expected for VioM and VirM. AunE, a second O‐MT involved in the biosynthesis of aurasperone A, shows different regioselectivity and low sequence similarity with that of VioM and VirM . Together with the cyclization pattern matching the NR‐PKS PT gene clusters, the homology of the O‐MTs corroborates the identified BGCs (Figure ) as being responsible for the biosyntheses of 2 and 3 .…”

Section: Methodsmentioning

confidence: 99%

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Diversity in Fungal Intermolecular Phenol Coupling of Polyketides: Regioselective Laccase‐Based Systems

et al. 2019

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Polyketides form a structurally diverse and pharmaceutically important class of secondary metabolites. Both diversity and biological activity are largely facilitated by post‐polyketide synthase tailoring including methylation, oxidation, reduction, glycosylation, and dimerization. Cytochrome P450 enzymes (CYPs), flavin‐dependent monooxygenases (FMOs), and laccases are known to catalyze phenol coupling in the biosynthesis of polyketide dimers. Polyketide homodimers resulting from enzyme catalysis are often formed in a highly regio‐ and stereoselective manner, in contrast to analogous nonenzymatic dimerization. Although it is known that CYPs and FMOs are capable of selectively generating one of several putative isomers, hitherto described laccases depend on auxiliary proteins to achieve similar selectivity. Herein, regioselective phenol coupling catalyzed by a fungal laccase is demonstrated. The heterologously produced Av‐VirL from Aspergillus viridinutans selectively generated the 6,6′‐homodimer of (R)‐semivioxanthin. Genome analysis is used to show that laccase‐based phenol‐coupling systems are widespread in fungi. Homologues of Av‐VirL were identified in the putative biosynthetic gene clusters of vioxanthin, xanthomegnin, and xanthoepocin, and of the perylenequinones hypocrellin A, elsinochrome A, and cercosporin. These findings show that laccases are capable of selective phenol coupling in the absence of auxiliary proteins.

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Section: Methodssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

Diversity in Fungal Intermolecular Phenol Coupling of Polyketides: Regioselective Laccase‐Based Systems

et al. 2019

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“…[10,11] Further,C YPs are known to catalyze the coupling reactioni nt he biosynthe-sis of the dimericn aphthopyrones nigerone (5)a nd aurasperone A( 7,S cheme 1). [12] These two metabolites are regioisomers, each exclusively formed by ad istinct Aspergillus strain and not occurring as ar egioisomericm ixture. This means that enzymes of one class (CYPs) can catalyzes elective dimerizations leading to different regioisomers.…”

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confidence: 99%

“…[16] As it would be responsible for ak ey step in the biosynthesis of such binaphthalenes, the identification of ap henol-coupling enzymec apable of catalyzing the dimerizationo ft orachrysone-8-O-methyl ether (1)b ecame ap riority.R ecently,t he two ascomycete CYPs BfoB and AunBw ere shown to dimerize the naphthopyrone rubrofusarin B, either to nigerone( 5)o rt oa urasperone A ( 7). [12] These two metabolites reflect the regiochemistry of rufoschweinitzin (2)a nd schweinitzinB (4), respectively,s oaCYP-catalyzed dimerization was supposed, at least in the case of dimerization in ascomycetes. The genome of X. schweinitzii BCC 1337f rom Thailandw as hence sequenced on an Illuminap latform and bioinformatically investigated.…”

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confidence: 99%

Enzymatic Formation of Rufoschweinitzin, a Binaphthalene from the Basidiomycete Cortinarius rufoolivaceus

et al. 2020

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WolfgangS teglich, [b] and MichaelM üller* [a] DedicatedtoProf. Rolf Huisgen on his 100 th birthday.Dimeric polyketides are widespreadf ungal secondary metabolites. They occur in both ascomycetes and basidiomycetes and, therefore, across fungal phyla.H ere we report the isolation of an ew binaphthalene, named rufoschweinitzin, from the basidiomycete Cortinarius rufoolivaceus. Rufoschweinitzin consists of two symmetrically 4,4'-coupled torachrysone-8-O-methyl ether moieties. Furthermore, we have identified ab inaphthalene biosynthetic gene clusteri na nu nrelated fungus, the ascomycete Xylaria schweinitzii. Heterologous expression of the encoded cytochrome P450 enzymev erifiedi ts coupling activity:d imerization of torachrysone-8-O-methyl ether led to the formation of rufoschweinitzin alongside ah itherto unknown regioisomer,n ow named alloschweinitzin. We have thusd emonstrated enzymatic formation of the basidiomycete's metabolite rufoschweinitzin and made the regiochemistry of alloschweinitzin accessible with an ascomycete-derived enzyme.Naturally occurring binaphthalenes have attracted the interest of scientists due to their auspicious bioactivity and their similarity to BINOL-type catalysts. [1][2][3][4][5] Nevertheless,t heir biosynthesis has not been investigated as yet, especially with regardt o the regio-ands tereoselective oxidative phenol coupling of the monomeric precursors.Recent research hasd emonstrated that different sets of enzymes are responsible for the dimerizationo fp olyketides in fungi. Laccases were shown to mediate regioselective CÀC bond formation,s ometimes depending on auxiliary proteins to be active or to introduce stereoinformation at the biaryl axis. [6][7][8][9] CytochromeP 450 enzymes (CYPs)a re also associated with phenol-coupling reactions.I nt he biosynthesis of bicoumarins, they control both regio-and stereoselectivity on their own, without the need for auxiliary proteins. [10,11] Further,C YPs are known to catalyze the coupling reactioni nt he biosynthe-sis of the dimericn aphthopyrones nigerone (5)a nd aurasperone A( 7,S cheme 1). [12] These two metabolites are regioisomers, each exclusively formed by ad istinct Aspergillus strain and not occurring as ar egioisomericm ixture. This means that enzymes of one class (CYPs) can catalyzes elective dimerizations leading to different regioisomers. The mechanismsb ehind this are unknown.Here, the isolation and characterization of an ew binaphthalene, named rufoschweinitzin (2), from the basidiomycete Cortinarius rufoolivaceus are presented.F urthermore, we also demonstrate enzymatic formation of 2 through the action of aC YP that is encoded in ab iosynthetic gene cluster( BGC) identified in the genome of the ascomycete Xylaria schweinitzii BCC 1337. Besides the coupling activity of the CYP,w eh ave verifiedt he activity of two other encoded enzymes-namely, two O-methyltransferases-through heterologous expression. As hypothesized, the two O-methyltransferasesm ethylate the monomeric precursor 6-hydroxymusizin (8)t op rovide torachry...

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“…Even in biosynthetic pathways of other dimeric g-naphthopyrones similar to ustilaginoidins,cytochrome P450 enzymes catalyze the dimerization reactions. [27] However,the group of laccases described herein show unprecedented selectivity in the formation of the biaryl bond, thus making this ar emarkable example of convergent evolution.…”

Section: Zuschriftenmentioning

confidence: 97%

Enantioselective Phenol Coupling by Laccases in the Biosynthesis of Fungal Dimeric Naphthopyrones

et al. 2019

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Biaryl compounds are ubiquitous metabolites that are often formed by dimerization through oxidative phenol coupling.Hindered rotation around the biaryl bond can cause axial chirality.I nn ature,d imerizations are catalyzed by oxidative enzymes such as laccases.T his class of enzymes is knownf or non-specific oxidase reactions while inherent enantioselectivity is hitherto unknown. Here,w ed escribe four related fungal laccases that catalyze g-naphthopyrone dimerization in ar egio-and atropselective manner.I nvitro assays revealed that three enzymes were highly P-selective (ee > 95 %), while one enzyme showed remarkable flexibility.I ts selectivity for M-or P-configured dimers varied depending on the reaction conditions.F or example,alower enzyme concentration yielded primarily (P)-ustilaginoidin A, whereas the Matropisomer was favored at higher concentration. These results demonstrate inherent enantioselectivity in an enzyme class that was previously thought to comprise only nonselective oxidases.

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Biaryl-Forming Enzymes from Aspergilli Exhibit Substrate-Dependent Stereoselectivity

Cited by 27 publications

References 28 publications

Diversity in Fungal Intermolecular Phenol Coupling of Polyketides: Regioselective Laccase‐Based Systems

Diversity in Fungal Intermolecular Phenol Coupling of Polyketides: Regioselective Laccase‐Based Systems

Enzymatic Formation of Rufoschweinitzin, a Binaphthalene from the Basidiomycete Cortinarius rufoolivaceus

Enantioselective Phenol Coupling by Laccases in the Biosynthesis of Fungal Dimeric Naphthopyrones

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