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Natural Product Enzymes in Biosynthesis and Biocatalysis

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Bioorganic Chemistry".

Deadline for manuscript submissions: closed (30 September 2018) | Viewed by 18015

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Prof. Dr. Tobias A. M. Gulder

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Department of Chemistry and Center for Integrated Protein Science Munich (CIPSM), Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
Interests: natural product biosynthesis; biocatalysis; chemo-enzymatic synthesis; metabolic engineering
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Dear Colleagues,

Nature provides a tremendous diversity of complex small molecules with intriguing strucutural and functional properties, in particular for biomedical applications. The biosynthetic machineries encoding these natural products are treasure troves for the discovery of valuable new enzymes catalyzing unprecedented transformations, ranging from highly regio- and stereoselective C-H-activation reactions to astonishing skelatal rearrangement sequences. In this Special Issue, we welcome research articles that take advantage of the arsenal of modern biomolecular and biochemical techniques to illuminate such biosynthetic transformations in vivo or in vitro and to utilize the respective proteins in biotechnological or chemo-enzymatic applications.

As Guest Editor, I cordially invite researchers to submit their recent advances in the field to this Special Issue of Molecules.

With best regards,

Prof. Dr. Tobias A. M. Gulder
Guest Editor

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Keywords

Biosynthesis
Biotechnology
Biocatalysis
Enzymes
Enzyme Engineering
Pathway Engineering
Natural Products

Published Papers (4 papers)

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Research

19 pages, 6787 KiB

Open AccessArticle

De Novo Biosynthesis of p-Coumaric Acid in E. coli with a trans-Cinnamic Acid 4-Hydroxylase from the Amaryllidaceae Plant Lycoris aurea

by Yikui Li, Jie Li, Binbin Qian, Li Cheng, Sheng Xu and Ren Wang

Molecules 2018, 23(12), 3185; https://doi.org/10.3390/molecules23123185 - 03 Dec 2018

Cited by 30 | Viewed by 7606

Abstract

p-Coumaric acid is a commercially available phenolcarboxylic acid with a great number of important applications in the nutraceutical, pharmaceutical, material and chemical industries. p-Coumaric acid has been biosynthesized in some engineered microbes, but the potential of the plant CYP450-involved biosynthetic route has not investigated in Escherichia coli. In the present study, a novel trans-cinnamic acid 4-hydroxylase (C4H) encoding the LauC4H gene was isolated from Lycoris aurea (L’ Hér.) Herb via rapid amplification of cDNA ends. Then, N-terminal 28 amino acids of LauC4H were characterized, for the subcellular localization, at the endoplasmic reticulum membrane in protoplasts of Arabidopsis thaliana. In E. coli, LauC4H without the N-terminal membrane anchor region was functionally expressed when fused with the redox partner of A. thaliana cytochrome P450 enzyme (CYP450), and was verified to catalyze the trans-cinnamic acid to p-coumaric acid transformation by whole-cell bioconversion, HPLC detection and LC-MS analysis as well. Further, with phenylalanine ammonia-lyase 1 of A. thaliana, p-coumaric acid was de novo biosynthesized from glucose as the sole carbon source via the phenylalanine route in the recombinant E. coli cells. By regulating the level of intracellular NADPH, the production of p-coumaric acid was dramatically improved by 9.18-fold, and achieved with a titer of 156.09 μM in shake flasks. The recombinant cells harboring functional LauC4H afforded a promising chassis for biological production of p-coumaric acid, even other derivatives, via a plant CYP450-involved pathway. Full article

(This article belongs to the Special Issue Natural Product Enzymes in Biosynthesis and Biocatalysis)

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11 pages, 3004 KiB

Open AccessArticle

Enzymatic Synthesis of Unnatural Ginsenosides Using a Promiscuous UDP-Glucosyltransferase from Bacillus subtilis

by Ting-Ting Zhang, Ting Gong, Zong-Feng Hu, An-Di Gu, Jin-Ling Yang and Ping Zhu

Molecules 2018, 23(11), 2797; https://doi.org/10.3390/molecules23112797 - 28 Oct 2018

Cited by 12 | Viewed by 3340

Abstract

Glycosylation, which is catalyzed by UDP-glycosyltransferases (UGTs), is an important biological modification for the structural and functional diversity of ginsenosides. In this study, the promiscuous UGT109A1 from Bacillus subtilis was used to synthesize unnatural ginsenosides from natural ginsenosides. UGT109A1 was heterologously expressed in Escherichia coli and then purified by Ni-NTA affinity chromatography. Ginsenosides Re, Rf, Rh1, and R1 were selected as the substrates to produce the corresponding derivatives by the recombinant UGT109A1. The results showed that UGT109A1 could transfer a glucosyl moiety to C3-OH of ginsenosides Re and R1, and C3-OH and C12-OH of ginsenosides Rf and Rh1, respectively, to produce unnatural ginsenosides 3,20-di-O-β-d-glucopyranosyl-6-O-[α-l-rhamnopyrano-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (1), 3,20-di-O-β-d-glucopyranosyl-6-O-[β-d-xylopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (6), 3-O-β-d-glucopyranosyl-6-O-[β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (3), 3,12-di-O-β-d-glucopyranosyl-6-O-[β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (2), 3,6-di-O-β-d-glucopyranosyl-dammar-24-ene-3β,6α,12β,20S-tetraol (5), and 3,6,12-tri-O-β-d-glucopyranosyl-dammar-24-ene-3β,6α,12β,20S-tetraol (4). Among the above products, 1, 2, 3, and 6 are new compounds. The maximal activity of UGT109A1 was achieved at the temperature of 40 °C, in the pH range of 8.0–10.0. The activity of UGT109A1 was considerably enhanced by Mg²⁺, Mn²⁺, and Ca²⁺, but was obviously reduced by Cu²⁺, Co²⁺, and Zn²⁺. The study demonstrated that UGT109A1 was effective in producing a series of unnatural ginsenosides through enzymatic reactions, which could pave a way to generate promising leads for new drug discovery. Full article

(This article belongs to the Special Issue Natural Product Enzymes in Biosynthesis and Biocatalysis)

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16 pages, 4263 KiB

Open AccessArticle

Optimization of Transesterification Reactions with CLEA-Immobilized Feruloyl Esterases from Thermothelomyces thermophila and Talaromyces wortmannii

by Anastasia Zerva, Io Antonopoulou, Josefine Enman, Laura Iancu, Peter Jütten, Ulrika Rova and Paul Christakopoulos

Molecules 2018, 23(9), 2403; https://doi.org/10.3390/molecules23092403 - 19 Sep 2018

Cited by 11 | Viewed by 3979

Abstract

Feruloyl esterases (FAEs, E.C. 3.1.1.73) are biotechnologically important enzymes with several applications in ferulic acid production from biomass, but also in synthesis of hydroxycinnamic acid derivatives. The use of such biocatalysts in commercial processes can become feasible by their immobilization, providing the advantages of isolation and recycling. In this work, eight feruloyl esterases, immobilized in cross-linked enzyme aggregates (CLEAs) were tested in regard to their transesterification performance, towards the production of prenyl ferulate (PFA) and arabinose ferulate (AFA). After solvent screening, comparison with the activity of respective soluble enzymes, and operational stability tests, FAE125 was selected as the most promising biocatalyst. A central composite design revealed the optimum conditions for each transesterification product, in terms of water content, time, and substrate ratio for both products, and temperature and enzyme load additionally for prenyl ferulate. The optimum product yields obtained were 83.7% for PFA and 58.1% for AFA. FAE125 CLEAs are stable in the optimum conditions of transesterification reactions, maintaining 70% residual activity after five consecutive reactions. Overall, FAE125 CLEAs seem to be able to perform as a robust biocatalyst, offering satisfactory yields and stability, and thus showing significant potential for industrial applications. Full article

(This article belongs to the Special Issue Natural Product Enzymes in Biosynthesis and Biocatalysis)

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15 pages, 1911 KiB

Open AccessArticle

Immobilized and Free Cells of Geotrichum candidum for Asymmetric Reduction of Ketones: Stability and Recyclability

by Hui Liu, Fayene Zeferino Ribeiro De Souza, Lan Liu and Bi-Shuang Chen

Molecules 2018, 23(9), 2144; https://doi.org/10.3390/molecules23092144 - 27 Aug 2018

Cited by 9 | Viewed by 2606

Abstract

Marine-derived fungus Geotrichum candidum AS 2.361 was previously reported by our group as an active strain for the enantioselective reduction of ketones. Although some other Geotrichum strains were also found from the terrestrial sources, information on their stability and reusability is scarce. Herein, the stabilities—in terms of pH tolerance, thermostability, and storage stability, and reusability—of G. candidum AS 2.361 were described for the asymmetric reduction of a series of aromatic ketones. Two differently immobilized cells (agar immobilization and calcium alginate immobilization) as well as free cells were prepared. For three substrates (1-(3-bromophenyl) ethan-1-one (1b), 1-(2-chlorophenyl) ethan-1-one (1d), and acetophenone (1g)) immobilized cells on agar showed a great improvement in the bioreduction activities compared to the free cells, increasing yields up to 97% with ee values of 99%. Cells immobilized on agar/calcium alginate could maintain more than 90% of the original activities within the assayed pH ranges of 3.5–11, while free cells were highly sensitive to alkaline and acidic conditions. Concerning thermostability, immobilized cells on agar kept 99% of their original activities after incubation at 60 °C for 1 h, while almost no activity was detected for the free cells under the same condition. Immobilized cells were stable at 4 °C for 80 days without any activity loss, while free cells started to decrease the activity after storage at 4 °C for six days. The immobilized cells retained almost 99% activity after four reuse cycles, while free cells lost almost all the activities at on the third cycle. Full article

(This article belongs to the Special Issue Natural Product Enzymes in Biosynthesis and Biocatalysis)

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