Discovery of a Two-Component Monooxygenase SnoaW/SnoaL2 Involved in Nogalamycin Biosynthesis

Siitonen, Vilja; Blauenburg, Bastian; Kallio, Pauli T.; Mäntsälä, Pekka; Metsä‐Ketelä, Mikko

doi:10.1016/j.chembiol.2012.04.009

Cited by 33 publications

(40 citation statements)

References 48 publications

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“…When we further investigated the enzymatic mechanism, a similar two-component monooxygenase SnoaW/SnoaL2 involved in nogalamycin biosynthesis was reported, and a reaction model was proposed (15). Our experiment results under anaerobic conditions, together with their proposal, led to replenishing the hydroxylation mechanism; the process resembles the reaction catalyzed by flavoenzymes, where the reduced flavin cofactor activates dioxygen to yield a semiquinone-superoxide radical pair (Fig.…”

Section: Resultsmentioning

confidence: 60%

Hydroxyl regioisomerization of anthracycline catalyzed by a four-enzyme cascade

Zhang

Gong

Zhou

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Ranking among the most effective anticancer drugs, anthracyclines represent an important family of aromatic polyketides generated by type II polyketide synthases (PKSs). After formation of polyketide cores, the post-PKS tailoring modifications endow the scaffold with various structural diversities and biological activities. Here we demonstrate an unprecedented four-enzyme-participated hydroxyl regioisomerization process involved in the biosynthesis of kosinostatin. First, KstA15 and KstA16 function together to catalyze a cryptic hydroxylation of the 4-hydroxyl-anthraquinone core, yielding a 1,4-dihydroxyl product, which undergoes a chemically challenging asymmetric reduction-dearomatization subsequently acted by KstA11; then, KstA10 catalyzes a region-specific reduction concomitant with dehydration to afford the 1-hydroxyl anthraquinone. Remarkably, the shunt product identifications of both hydroxylation and reduction-dehydration reactions, the crystal structure of KstA11 with bound substrate and cofactor, and isotope incorporation experiments reveal mechanistic insights into the redox dearomatization and rearomatization steps. These findings provide a distinguished tailoring paradigm for type II PKS engineering.biosynthesis | C-4 deoxyanthracycline | two-component hydroxylase | NmrA-like short-chain dehydrogenase | dehydroxylation

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Section: Resultsmentioning

confidence: 60%

Hydroxyl regioisomerization of anthracycline catalyzed by a four-enzyme cascade

Zhang

Gong

Zhou

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…1) (9), which contains the C5′′-C2 bond, but has (S) stereochemistry at C4′′, in contrast to the 4′′-(R) configuration seen in 1. The functions of most gene products residing in the gene cluster have already been mapped (1,9,14), which directed us toward two putative α-KG-and Fe(II)-dependent oxygenases, snoN and snoK, as the likely candidate genes for late stage tailoring reactions.…”

Section: Resultsmentioning

confidence: 99%

Divergent non-heme iron enzymes in the nogalamycin biosynthetic pathway

Siitonen

Selvaraj

Niiranen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Nogalamycin, an aromatic polyketide displaying high cytotoxicity, has a unique structure, with one of the carbohydrate units covalently attached to the aglycone via an additional carbon-carbon bond. The underlying chemistry, which implies a particularly challenging reaction requiring activation of an aliphatic carbon atom, has remained enigmatic. Here, we show that the unusual C5′′-C2 carbocyclization is catalyzed by the non-heme iron α-ketoglutarate (α-KG)-dependent SnoK in the biosynthesis of the anthracycline nogalamycin. The data are consistent with a mechanistic proposal whereby the Fe(IV) = O center abstracts the H5′′ atom from the amino sugar of the substrate, with subsequent attack of the aromatic C2 carbon on the radical center. We further show that, in the same metabolic pathway, the homologous SnoN (38% sequence identity) catalyzes an epimerization step at the adjacent C4′′ carbon, most likely via a radical mechanism involving the Fe(IV) = O center. SnoK and SnoN have surprisingly similar active site architectures considering the markedly different chemistries catalyzed by the enzymes. Structural studies reveal that the differences are achieved by minor changes in the alignment of the substrates in front of the reactive ferryl-oxo species. Our findings significantly expand the repertoire of reactions reported for this important protein family and provide an illustrative example of enzyme evolution.natural product biosynthesis | Streptomyces | crystal structure | α-ketoglutarate-dependent oxygenase | iron-dependent oxygenase

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“…Gene duplication and catalytic promiscuity have been important in the evolution of the unique substructure. This chemistry originates from an unusual two‐component mono‐oxygenase system that is responsible for the installation of the C1 hydroxyl group . The system is composed of an SDR‐enzyme, SnoaW, and a protein SnoaL2 homologous to canonical polyketide cyclases such as SnoaL .…”

Section: Gene Duplication Allows Formation Of More Complex Chemical Smentioning

confidence: 99%

A pharmaceutical model for the molecular evolution of microbial natural products

Fewer

Metsä‐Ketelä

2019

The FEBS Journal

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Microbes are talented chemists with the ability to generate tremendously complex and diverse natural products which harbor potent biological activities. Natural products are produced using sets of specialized biosynthetic enzymes encoded by secondary metabolism pathways. Here, we present a two‐step evolutionary model to explain the diversification of biosynthetic pathways that account for the proliferation of these molecules. We argue that the appearance of natural product families has been a slow and infrequent process. The first step led to the original emergence of bioactive molecules and different classes of natural products. However, much of the chemical diversity observed today has resulted from the endless modification of the ancestral biosynthetic pathways. The second step rapidly modulates the pre‐existing biological activities to increase their potency and to adapt to changing environmental conditions. We highlight the importance of enzyme promiscuity in this process, as it facilitates both the incorporation of horizontally transferred genes into secondary metabolic pathways and the functional differentiation of proteins to catalyze novel chemistry. We provide examples where single point mutations or recombination events have been sufficient for new enzymatic activities to emerge. A unique feature in the evolution of microbial secondary metabolism is that gene duplication is not essential but offers opportunities to synthesize more complex metabolites. Microbial natural products are highly important for the pharmaceutical industry due to their unique bioactivities. Therefore, understanding the natural mechanisms leading to the formation of diverse metabolic pathways is vital for future attempts to utilize synthetic biology for the generation of novel molecules.

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Discovery of a Two-Component Monooxygenase SnoaW/SnoaL2 Involved in Nogalamycin Biosynthesis

Cited by 33 publications

References 48 publications

Hydroxyl regioisomerization of anthracycline catalyzed by a four-enzyme cascade

Hydroxyl regioisomerization of anthracycline catalyzed by a four-enzyme cascade

Divergent non-heme iron enzymes in the nogalamycin biosynthetic pathway

A pharmaceutical model for the molecular evolution of microbial natural products

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