Publications by authors named "Jeroen S Dickschat"

172 Publications

The Mechanism of Dehydrating Bimodules in trans-Acyltransferase Polyketide Biosynthesis: A Showcase Study on Hepatoprotective Hangtaimycin.

Angew Chem Int Ed Engl 2021 Jul 4. Epub 2021 Jul 4.

Wuhan University, School of Pharmaceutical Sciences, 185 East Lake Road, Wuchang District, 430071, Wuhan, CHINA.

A bioassay-guided fractionation led to the isolation of hangtaimycin (HTM) from Streptomyces spectabilis CCTCC M2017417 and the discovery of its hepatoprotective properties. Structure elucidation by NMR suggested the need for a structural revision. A putative HTM degradation product was also isolated and its structure was confirmed by total synthesis. The biosynthetic gene cluster was identified and resembles a hybrid trans-AT PKS/NRPS biosynthetic machinery whose first PKS enzyme contains an internal dehydrating bimodule, which is usually found split in other trans-AT PKSs. The mechanisms of such dehydrating bimodules have often been proposed, but have never been deeply investigated. Here we present in vivo mutations and in vitro enzymatic experiments that give first and detailed mechanistic insights into catalysis by dehydrating bimodules.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202106250DOI Listing
July 2021

A Flavoprotein Dioxygenase Steers Bacterial Tropone Biosynthesis via Coenzyme A-Ester Oxygenolysis and Ring Epoxidation.

J Am Chem Soc 2021 Jul 1;143(27):10413-10421. Epub 2021 Jul 1.

Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.

Bacterial tropone natural products such as tropolone, tropodithietic acid, or the roseobacticides play crucial roles in various terrestrial and marine symbiotic interactions as virulence factors, antibiotics, algaecides, or quorum sensing signals. We now show that their poorly understood biosynthesis depends on a shunt product from aerobic CoA-dependent phenylacetic acid catabolism that is salvaged by the dedicated acyl-CoA dehydrogenase-like flavoenzyme TdaE. Further characterization of TdaE revealed an unanticipated complex catalysis, comprising substrate dehydrogenation, noncanonical CoA-ester oxygenolysis, and final ring epoxidation. The enzyme thereby functions as an archetypal flavoprotein dioxygenase that incorporates both oxygen atoms from O into the substrate, most likely involving flavin-N5-peroxide and flavin-N5-oxide species for consecutive CoA-ester cleavage and epoxidation, respectively. The subsequent spontaneous decarboxylation of the reactive enzyme product yields tropolone, which serves as a key virulence factor in rice panicle blight caused by pathogenic edaphic . Alternatively, the TdaE product is most likely converted to more complex sulfur-containing secondary metabolites such as tropodithietic acid from predominant marine (e.g., ).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.1c04996DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8283759PMC
July 2021

The Termite Fungal Cultivar Combines Diverse Enzymes and Oxidative Reactions for Plant Biomass Conversion.

mBio 2021 06 15;12(3):e0355120. Epub 2021 Jun 15.

Group of Chemical Biology of Microbe-Host Interactions, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany.

Macrotermitine termites have domesticated fungi in the genus as their primary food source using predigested plant biomass. To access the full nutritional value of lignin-enriched plant biomass, the termite-fungus symbiosis requires the depolymerization of this complex phenolic polymer. While most previous work suggests that lignocellulose degradation is accomplished predominantly by the fungal cultivar, our current understanding of the underlying biomolecular mechanisms remains rudimentary. Here, we provide conclusive omics and activity-based evidence that employs not only a broad array of carbohydrate-active enzymes (CAZymes) but also a restricted set of oxidizing enzymes (manganese peroxidase, dye decolorization peroxidase, an unspecific peroxygenase, laccases, and aryl-alcohol oxidases) and Fenton chemistry for biomass degradation. We propose for the first time that induces hydroquinone-mediated Fenton chemistry (Fe + HO + H → Fe + OH + HO) using a herein newly described 2-methoxy-1,4-dihydroxybenzene (2-MHQ, compound 19)-based electron shuttle system to complement the enzymatic degradation pathways. This study provides a comprehensive depiction of how efficient biomass degradation by means of this ancient insect's agricultural symbiosis is accomplished. Fungus-growing termites have optimized the decomposition of recalcitrant plant biomass to access valuable nutrients by engaging in a tripartite symbiosis with complementary contributions from a fungal mutualist and a codiversified gut microbiome. This complex symbiotic interplay makes them one of the most successful and important decomposers for carbon cycling in Old World ecosystems. To date, most research has focused on the enzymatic contributions of microbial partners to carbohydrate decomposition. Here, we provide genomic, transcriptomic, and enzymatic evidence that also employs redox mechanisms, including diverse ligninolytic enzymes and a Fenton chemistry-based hydroquinone-catalyzed lignin degradation mechanism, to break down lignin-rich plant material. Insights into these efficient decomposition mechanisms reveal new sources of efficient ligninolytic agents applicable for energy generation from renewable sources.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mBio.03551-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262964PMC
June 2021

1,2- or 1,3-Hydride Shifts: What Controls Guaiane Biosynthesis?

Chemistry 2021 Jul 26;27(38):9758-9762. Epub 2021 May 26.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany.

A systematic computational study addressing the entire chemical space of guaianes in conjunction with an analysis of all known compounds shows that 1,3-hydride shifts are rare events in guaiane biosynthesis. As demonstrated here, 1,3-hydride shifts towards guaianes can only be realized for two stereochemically well defined out of numerous possible stereoisomeric skeletons. One example is given by the mechanism of guaia-4(15)-en-11-ol synthase from California poplar, an enzyme that yields guaianes with unusual stereochemical properties. The general results from DFT calculations were experimentally verified through isotopic-labeling experiments with guaia-4(15)-en-11-ol synthase.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202101371DOI Listing
July 2021

Rerouting and Improving Dauc-8-en-11-ol Synthase from Streptomyces venezuelae to a High Yielding Biocatalyst.

Chemistry 2021 May 1;27(29):7923-7929. Epub 2021 May 1.

Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms Universität Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany.

The dauc-8-en-11-ol synthase from Streptomyces venezuelae was investigated for its catalytic activity towards alternative terpene precursors, specifically designed to enable new cyclisation pathways. Exchange of aromatic amino acid residues at the enzyme surface by site-directed mutagenesis led to a 4-fold increase of the yield in preparative scale incubations, which likely results from an increased enzyme stability instead of improved enzyme kinetics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202100962DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8252471PMC
May 2021

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the group yields garlic oil constituents.

Beilstein J Org Chem 2021 26;17:569-580. Epub 2021 Feb 26.

Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.

Two analogues of 3-(dimethylsulfonio)propanoate (DMSP), 3-(diallylsulfonio)propanoate (DAllSP), and 3-(allylmethylsulfonio)propanoate (AllMSP), were synthesized and fed to marine bacteria from the clade. These bacteria are able to degrade DMSP into dimethyl sulfide and methanethiol. The DMSP analogues were also degraded, resulting in the release of allylated sulfur volatiles known from garlic. For unknown compounds, structural suggestions were made based on their mass spectrometric fragmentation pattern and confirmed by the synthesis of reference compounds. The results of the feeding experiments allowed to conclude on the substrate tolerance of DMSP degrading enzymes in marine bacteria.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.17.51DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7934745PMC
February 2021

Identification of volatiles from six marine strains.

Beilstein J Org Chem 2021 11;17:420-430. Epub 2021 Feb 11.

Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.

The volatiles emitted from six marine species of the genus were investigated by GC-MS. Besides several known compounds including dimethyl trisulfide and -methyl methanethiosulfonate, the sulfur-containing compounds ethyl ()-3-(methylsulfanyl)acrylate and 2-(methyldisulfanyl)benzothiazole were identified and their structures were verified by synthesis. Feeding experiments with [-H]methionine, [-C]methionine and [S]-3-(dimethylsulfonio)propanoate (DMSP) resulted in the high incorporation into dimethyl trisulfide and -methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl ()-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the strains are capable of methionine and DMSP degradation to widespread sulfur volatiles, but the analysis of trace compounds in natural samples must be taken with care.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.17.38DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884881PMC
February 2021

The mass spectrometric fragmentation mechanisms of catenulane and isocatenulane diterpenes.

Org Biomol Chem 2021 03;19(10):2224-2232

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.

Two new diterpene derivatives were obtained by semisynthesis from enzymatically generated catenul-14-en-6-ol. The EI-MS fragmentation mechanisms of three enzyme products and the two semisynthetic derivatives were investigated by extensive 13C-labelling experiments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d1ob00160dDOI Listing
March 2021

The Sesquiterpene Synthase PtTPS5 Produces (1,5,7,10)-Guaia-4(15)-en-11-ol and (1,7,10)-Guaia-4-en-11-ol in Oomycete-Infected Poplar Roots.

Molecules 2021 Jan 21;26(3). Epub 2021 Jan 21.

Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany.

Pathogen infection often leads to the enhanced formation of specialized plant metabolites that act as defensive barriers against microbial attackers. In this study, we investigated the formation of potential defense compounds in roots of the Western balsam poplar () upon infection with the generalist root pathogen (Oomycetes). infection led to an induced accumulation of terpenes, aromatic compounds, and fatty acids in poplar roots. Transcriptome analysis of uninfected and -infected roots revealed a terpene synthase gene that was significantly induced upon pathogen infection. PtTPS5 had been previously reported as a sesquiterpene synthase producing two unidentified sesquiterpene alcohols as major products and hedycaryol as a minor product. Using heterologous expression in , enzyme assays with deuterium-labeled substrates, and NMR analysis of reaction products, we could identify the major PtTPS5 products as (1,5,7,10)-guaia-4(15)-en-11-ol and (1,7,10)-guaia-4-en-11-ol, with the former being a novel compound. The transcript accumulation of in uninfected and -infected poplar roots matched the accumulation of (1,5,7,10)-guaia-4(15)-en-11-ol, (1,7,10)-guaia-4-en-11-ol, and hedycaryol in this tissue, suggesting that PtTPS5 likely contributes to the pathogen-induced formation of these compounds in planta.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules26030555DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7866031PMC
January 2021

double bond formation in polyketide biosynthesis.

Nat Prod Rep 2021 Jan 21. Epub 2021 Jan 21.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.

Covering: up to 2020Polyketides form a large group of bioactive secondary metabolites that usually contain one or more double bonds. Although most of the double bonds found in polyketides are trans or E-configured, several cases are known in which cis or Z-configurations are observed. Double bond formation by polyketide synthases (PKSs) is widely recognised to be catalysed by ketoreduction and subsequent dehydration of the acyl carrier protein (ACP)-tethered 3-ketoacyl intermediate in the PKS biosynthetic assembly line with a specific stereochemical course in which the ketoreduction step determines the usual trans or more rare cis double bond configuration. Occasionally, other mechanisms for the installation of cis double bonds such as double bond formation during chain release or post-PKS modifications including, amongst others, isomerisations or double bond installations by oxidation are observed. This review discusses the peculiar mechanisms of cis double bond formation in polyketide biosynthesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0np00091dDOI Listing
January 2021

Mechanistic divergence between (4,7)-germacra-(1(10),5)-dien-11-ol synthases from and .

Org Biomol Chem 2021 01;19(2):370-374

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.

The main product of DpTPS9 from the social amoeba Dictyostelium purpureum was identified as (4S,7R)-germacra-(1(10)E,5E)-dien-11-ol that is also known as an intermediate of bacterial geosmin synthase, but the experimentally verified cyclisation mechanisms differ. Together with the low sequence identity this points to convergent evolution. The functionality of selected residues in DpTPS9 was investigated via site-directed mutagenesis experiments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0ob02361bDOI Listing
January 2021

On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A-C.

Beilstein J Org Chem 2020 19;16:2807-2819. Epub 2020 Nov 19.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53127 Bonn, Germany.

A C-labelling was introduced into each individual carbon of the recently discovered sestermobaraenes by the enzymatic conversion of the correspondingly C-labelled isoprenyl diphosphate precursors with the sestermobaraene synthase from . The main compounds sestermobaraenes A, B, and C were analysed by gas chromatography-mass spectrometry (GC-MS), allowing for a deep mechanistic investigation of the electron impact mass spectrometry (EIMS) fragmentation reactions of these sesterterpene hydrocarbons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.16.231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7684692PMC
November 2020

Diterpene Biosynthesis in Catenulispora acidiphila: On the Mechanism of Catenul-14-en-6-ol Synthase.

Angew Chem Int Ed Engl 2021 01 10;60(3):1488-1492. Epub 2020 Dec 10.

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany.

A new diterpene synthase from the actinomycete Catenulispora acidiphila was identified and the structures of its products were elucidated, including the absolute configurations by an enantioselective deuteration approach. The mechanism of the cationic terpene cyclisation cascade was deeply studied through the use of isotopically labelled substrates and of substrate analogues with partially blocked reactivity, resulting in derailment products that gave further insights into the intermediates along the cascade. Their chemistry was studied, leading to the biomimetic synthesis of a diterpenoid analogue of a brominated sesquiterpene known from the red seaweed Laurencia microcladia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202014180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7839432PMC
January 2021

Revision of the Cyclisation Mechanism for the Diterpene Spiroviolene and Investigations of Its Mass Spectrometric Fragmentation.

Chembiochem 2021 Mar 10;22(5):850-854. Epub 2020 Nov 10.

Kekulé Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany.

The diterpene spiroviolene, its diterpene synthase from Streptomyces violens and the experimentally determined terpene cyclisation mechanism were reported in 2017. Recently, the structure of spiroviolene was revised based on a total synthesis, with consequences for the cyclisation mechanism. Herein, a reinvestigation of the terpene cyclisation to spiroviolene and the mass spectrometric fragmentation mechanism investigated by C-labelling experiments are presented.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbic.202000682DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7983979PMC
March 2021

Biosynthetic Gene Cluster for Asperterpenols A and B and the Cyclization Mechanism of Asperterpenol A Synthase.

Org Lett 2020 10 10;22(19):7552-7555. Epub 2020 Sep 10.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.

The biosynthetic gene cluster for the sesterterpenoids asperterpenols A and B from CBS121601 is described. The cluster contains two genes, for a chimeric sesterterpene synthase and - for a cytochrome P450 monooxygenase. The cyclization mechanism of the asperterpenol A synthase, catalyzing the formation of a unique sesterterpene with a 6/6/8/5 tetracyclic ring system, was studied using isotopically labeled terpene precursors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.0c02748DOI Listing
October 2020

Volatiles from the Psychrotolerant Bacterium Chryseobacterium polytrichastri.

Chembiochem 2020 12 16;21(24):3608-3617. Epub 2020 Sep 16.

Kekulé Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany.

The flavobacterium Chryseobacterium polytrichastri was investigated for its volatile profile by use of a closed-loop stripping apparatus (CLSA) and subsequent GC-MS analysis. The analyses revealed a rich headspace extract with 71 identified compounds. Compound identification was based on a comparison to library mass spectra for known compounds and on a synthesis of authentic standards for unknowns. Important classes were phenylethyl amides and a series of corresponding imines and pyrroles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbic.202000503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756357PMC
December 2020

The Biosynthetic Gene Cluster for Sestermobaraenes-Discovery of a Geranylfarnesyl Diphosphate Synthase and a Multiproduct Sesterterpene Synthase from Streptomyces mobaraensis.

Angew Chem Int Ed Engl 2020 11 31;59(45):19961-19965. Epub 2020 Aug 31.

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany.

A biosynthetic gene cluster from Streptomyces mobaraensis encoding the first cases of a bacterial geranylfarnesyl diphosphate synthase and a type I sesterterpene synthase was identified. The structures of seven sesterterpenes produced by these enzymes were elucidated, including their absolute configurations. The enzyme mechanism of the sesterterpene synthase was investigated by extensive isotope labeling experiments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202010084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693059PMC
November 2020

On the mechanism of ophiobolin F synthase and the absolute configuration of its product by isotopic labelling experiments.

Org Biomol Chem 2020 Aug 29;18(31):6072-6076. Epub 2020 Jul 29.

Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.

An ophiobolin F synthase homolog was discovered from Aspergillus calidoustus CBS121601. The cyclisation mechanism of this terpene synthase was investigated by extensive isotopic labelling experiments and the absolute configuration of its product ophiobolin F was elucidated by enantioselective deuteration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0ob01470bDOI Listing
August 2020

Diving into the world of marine 2,11-cyclized cembranoids: a summary of new compounds and their biological activities.

Nat Prod Rep 2020 10 27;37(10):1367-1383. Epub 2020 May 27.

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, China.

Covering: 2010 to 2020The class of 2,11-cyclized cembranoids is particularly widespread in marine Octocorallia, especially Alcyonacea and Gorgonacea, and has been extensively studied. Following a previous review published in 2010, the accumulated knowledge from the past decade will be presented here. All 2,11-cyclized cembranoids share a bicyclo[8.4.0]tetradecane core that is in most of the known compounds oxidatively modified to result in the 15-oxatricyclo[6.6.1.0]pentadecane system. Multiple further oxidation and acylation patterns can be observed, while halogenated compounds are surprisingly rare. One new sulfur-containing and a few seco-compounds have also been reported. The biosynthetic pathways to this fascinating class of natural products have not been studied to date, but a plausible biosynthetic hypothesis is presented that allows for a structured discussion of the compounds according to their carbon skeletons and oxidation patterns. Biological activities towards 2,11-cyclized diterpenes are also included.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0np00016gDOI Listing
October 2020

Germacrene A-A Central Intermediate in Sesquiterpene Biosynthesis.

Chemistry 2020 Dec 30;26(72):17318-17341. Epub 2020 Sep 30.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany.

This review summarises known sesquiterpenes whose biosyntheses proceed through the intermediate germacrene A. First, the occurrence and biosynthesis of germacrene A in Nature and its peculiar chemistry will be highlighted, followed by a discussion of 6-6 and 5-7 bicyclic compounds and their more complex derivatives. For each compound the absolute configuration, if it is known, and the reasoning for its assignment is presented.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202002163DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821278PMC
December 2020

Two Diterpene Synthases from Chryseobacterium: Chryseodiene Synthase and Wanjudiene Synthase.

Angew Chem Int Ed Engl 2020 07 18;59(29):11943-11947. Epub 2020 May 18.

Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany.

Two bacterial diterpene synthases (DTSs) from Chryseobacterium were characterised. The first enzyme yielded the new compound chryseodiene that closely resembles the known fusicoccane diterpenes from fungi, but its experimentally and computationally studied cyclisation mechanism is fundamentally different to the mechanism of fusicoccadiene synthase. The second enzyme produced wanjudiene, a diterpene hydrocarbon with a new skeleton, besides traces of the enantiomer of bonnadiene that was recently discovered from Allokutzneria albata.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202004691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7383580PMC
July 2020

Sesquiterpene synthases for bungoene, pentalenene and epi-isozizaene from Streptomyces bungoensis.

Org Biomol Chem 2020 06;18(24):4547-4550

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.

A sesquiterpene synthase from Streptomyces bungoensis was characterised and produces the new compound bungoene. The enzyme mechanism was deeply investigated using isotopically labelled substrates. Two other enzymes from S. bungoensis made epi-isozizaene and pentalenene. Synthetic oxidative chemistry towards structurally related fusagramineol and pentalenal was explored.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0ob00606hDOI Listing
June 2020

Nature-driven approaches to non-natural terpene analogues.

Nat Prod Rep 2020 08 18;37(8):1080-1097. Epub 2020 Feb 18.

Institute of Organic Chemistry and Center of Biomolecular Drug Research (BMWZ), Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany.

Covering: up to 2019The reactions catalysed by terpene synthases belong to the most complex and fascinating cascade-type transformations in Nature. Although many accept only one natural terpene precursor and convert it with high selectivity into only one product, several of these remarkable biocatalysts were recently shown to have a surprising plasticity towards non-natural substrate analogues. For an easy access to the topic also for readers who are new to the field, this review will first briefly cover the principles of natural terpene biosynthesis. This is followed by a chapter that highlights purely chemical transformations mimicking terpene synthase catalysed reactions. Then, the main focus of this article will shed light on the recent advances of terpene synthase catalysed transformations of synthetic substrate analogues. As will be demonstrated, a simple conceptual approach extensively broadens the chemical space that can be reached with terpene synthases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9np00055kDOI Listing
August 2020

The architecture of the diaminobutyrate acetyltransferase active site provides mechanistic insight into the biosynthesis of the chemical chaperone ectoine.

J Biol Chem 2020 02 22;295(9):2822-2838. Epub 2020 Jan 22.

Center for Structural Studies, Heinrich-Heine University Düsseldorf, D-40225 Düsseldorf, Germany; Institute of Biochemistry, Heinrich-Heine University Düsseldorf, D-40225 Düsseldorf, Germany. Electronic address:

Ectoine is a solute compatible with the physiologies of both prokaryotic and eukaryotic cells and is widely synthesized by bacteria as an osmotic stress protectant. Because it preserves functional attributes of proteins and macromolecular complexes, it is considered a chemical chaperone and has found numerous practical applications. However, the mechanism of its biosynthesis is incompletely understood. The second step in ectoine biosynthesis is catalyzed by l-2,4-diaminobutyrate acetyltransferase (EctA; EC 2.3.1.178), which transfers the acetyl group from acetyl-CoA to EctB-formed l-2,4-diaminobutyrate (DAB), yielding -γ-acetyl-l-2,4-diaminobutyrate (-γ-ADABA), the substrate of ectoine synthase (EctC). Here, we report the biochemical and structural characterization of the EctA enzyme from the thermotolerant bacterium (). We found that ()EctA forms a homodimer whose enzyme activity is highly regiospecific by producing -γ-ADABA but not the ectoine catabolic intermediate -α-acetyl-l-2,4-diaminobutyric acid. High-resolution crystal structures of ()EctA (at 1.2-2.2 Å resolution) (i) for its apo-form, (ii) in complex with CoA, (iii) in complex with DAB, (iv) in complex with both CoA and DAB, and (v) in the presence of the product -γ-ADABA were obtained. To pinpoint residues involved in DAB binding, we probed the structure-function relationship of ()EctA by site-directed mutagenesis. Phylogenomics shows that EctA-type proteins from both Bacteria and Archaea are evolutionarily highly conserved, including catalytically important residues. Collectively, our biochemical and structural findings yielded detailed insights into the catalytic core of the EctA enzyme that laid the foundation for unraveling its reaction mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA119.011277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7049965PMC
February 2020

Terpenes.

Beilstein J Org Chem 2019 13;15:2966-2967. Epub 2019 Dec 13.

Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.15.292DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941409PMC
December 2019

Enzymatic Synthesis of Methylated Terpene Analogues Using the Plasticity of Bacterial Terpene Synthases.

Chemistry 2020 Feb 30;26(10):2178-2182. Epub 2020 Jan 30.

Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany.

Methylated analogues of isopentenyl diphosphate were synthesised and enzymatically incorporated into methylated terpenes. A detailed stereochemical analysis of the obtained products is presented. The methylated terpene precursors were also used in conjunction with various isotopic labellings to gain insights into the mechanisms of their enzymatic formation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.201905827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065205PMC
February 2020

Biochemical and Mechanistic Characterization of the Fungal Reverse 1-Dimethylallyltryptophan Synthase DMATS1.

ACS Chem Biol 2019 12 5;14(12):2922-2931. Epub 2019 Dec 5.

Kekulé Institut für Organische Chemie und Biochemie , Rheinische Friedrich Wilhelms-Universität Bonn , Gerhard-Domagk-Strasse 1 , 53121 Bonn , Germany.

Dimethylallyltryptophan synthases catalyze the regiospecific transfer of (oligo)prenylpyrophosphates to aromatic substrates like tryptophan derivatives. These reactions are key steps in many biosynthetic pathways of fungal and bacterial secondary metabolites. investigations on recombinant DMATS1 from identified the enzyme as the first selective reverse tryptophan--1 prenyltransferase of fungal origin. The enzyme was also able to catalyze the reverse -geranylation of tryptophan. DMATS1 was shown to be phylogenetically related to fungal tyrosine -prenyltransferases and fungal 7-DMATS. Like these enzymes, DMATS1 was able to convert tyrosine into its regularly -prenylated derivative. Investigation of the binding sites of DMATS1 by homology modeling and comparison to the crystal structure of 4-DMATS FgaPT2 showed an almost identical site for DMAPP binding but different residues for tryptophan coordination. Several putative active site residues were verified by site directed mutagenesis of DMATS1. Homology models of the phylogenetically related enzymes showed similar tryptophan binding residues, pointing to a unified substrate binding orientation of tryptophan and DMAPP, which is distinct from that in FgaPT2. Isotopic labeling experiments showed the reaction catalyzed by DMATS1 to be nonstereospecific. Based on these data, a detailed mechanism for DMATS1 catalysis is proposed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschembio.9b00828DOI Listing
December 2019

Characterization of Micromonocyclol Synthase from the Marine Actinomycete .

Org Lett 2019 12 8;21(23):9442-9445. Epub 2019 Nov 8.

Kekulé-Institute for Organic Chemistry and Biochemistry , University of Bonn , Gerhard-Domagk-Strasse 1 , 53121 Bonn , Germany.

As a member of a large phylogenetic clade of enzymes in , a terpene synthase from is functionally characterized to produce micromonocyclol. This diterpene alcohol features a rare 15-membered ring, which prevented elucidation of the only stereocenter by labeling experiments. This problem was addressed by chemical transformation into bicyclic brominated derivatives, whose rigidified skeletons allowed for a stereochemical assignment. Using this strategy, a complete stereochemical model of the cyclization mechanism was also elaborated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.9b03654DOI Listing
December 2019

Characterisation of three terpene synthases for β-barbatene, β-araneosene and nephthenol from social amoebae.

Chem Commun (Camb) 2019 Oct;55(88):13255-13258

Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.

The products of three terpene synthases from two social amoebae, Dictyostelium discoideum and Dictyostelium purpureum, were identified, showing sesquiterpene synthase activity for one and diterpene synthase activity for the other two enzymes. Site-directed mutagenesis experiments revealed the importance of a newly identfied highly conserved residue for catalytic activity. For one of the enzyme products, β-araneosene, a bromonium ion induced transannular cyclisation was investigated, yielding the first brominated derivatives of this diterpene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc07681fDOI Listing
October 2019

Mechanistic Studies on Trichoacorenol Synthase from Amycolatopsis benzoatilytica.

Chembiochem 2020 03 7;21(6):807-810. Epub 2019 Nov 7.

Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany.

Isotopic labeling experiments performed with a newly identified bacterial trichoacorenol synthase established a 1,5-hydride shift occurring in the cyclization mechanism. During EI-MS analysis, major fragments of the sesquiterpenoid were shown to arise via cryptic hydrogen movements. Therefore, the interpretation of earlier results regarding the cyclization mechanism obtained by feeding experiments in Trichoderma is revised.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbic.201900584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7155024PMC
March 2020