1
|
Garces Daza F, Haitz F, Born A, Boles E. An optimized reverse β-oxidation pathway to produce selected medium-chain fatty acids in Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:71. [PMID: 37101299 PMCID: PMC10134560 DOI: 10.1186/s13068-023-02317-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/06/2023] [Indexed: 04/28/2023]
Abstract
BACKGROUND Medium-chain fatty acids are molecules with applications in different industries and with growing demand. However, the current methods for their extraction are not environmentally sustainable. The reverse β-oxidation pathway is an energy-efficient pathway that produces medium-chain fatty acids in microorganisms, and its use in Saccharomyces cerevisiae, a broadly used industrial microorganism, is desired. However, the application of this pathway in this organism has so far either led to low titers or to the predominant production of short-chain fatty acids. RESULTS We genetically engineered Saccharomyces cerevisiae to produce the medium-chain fatty acids hexanoic and octanoic acid using novel variants of the reverse β-oxidation pathway. We first knocked out glycerolphosphate dehydrogenase GPD2 in an alcohol dehydrogenases knock-out strain (△adh1-5) to increase the NADH availability for the pathway, which significantly increased the production of butyric acid (78 mg/L) and hexanoic acid (2 mg/L) when the pathway was expressed from a plasmid with BktB as thiolase. Then, we tested different enzymes for the subsequent pathway reactions: the 3-hydroxyacyl-CoA dehydrogenase PaaH1 increased hexanoic acid production to 33 mg/L, and the expression of enoyl-CoA hydratases Crt2 or Ech was critical to producing octanoic acid, reaching titers of 40 mg/L in both cases. In all cases, Ter from Treponema denticola was the preferred trans-enoyl-CoA reductase. The titers of hexanoic acid and octanoic acid were further increased to almost 75 mg/L and 60 mg/L, respectively, when the pathway expression cassette was integrated into the genome and the fermentation was performed in a highly buffered YPD medium. We also co-expressed a butyryl-CoA pathway variant to increase the butyryl-CoA pool and support the chain extension. However, this mainly increased the titers of butyric acid and only slightly increased that of hexanoic acid. Finally, we also tested the deletion of two potential medium-chain acyl-CoA depleting reactions catalyzed by the thioesterase Tes1 and the medium-chain fatty acyl CoA synthase Faa2. However, their deletion did not affect the production titers. CONCLUSIONS By engineering the NADH metabolism and testing different reverse β-oxidation pathway variants, we extended the product spectrum and obtained the highest titers of octanoic acid and hexanoic acid reported in S. cerevisiae. Product toxicity and enzyme specificity must be addressed for the industrial application of the pathway in this organism.
Collapse
Affiliation(s)
- Fernando Garces Daza
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe-Universität Frankfurt Am Main, Max-von-Laue-Str.9, 60438, Frankfurt am Main, Germany
| | - Fabian Haitz
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe-Universität Frankfurt Am Main, Max-von-Laue-Str.9, 60438, Frankfurt am Main, Germany
| | - Alice Born
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe-Universität Frankfurt Am Main, Max-von-Laue-Str.9, 60438, Frankfurt am Main, Germany
| | - Eckhard Boles
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe-Universität Frankfurt Am Main, Max-von-Laue-Str.9, 60438, Frankfurt am Main, Germany.
| |
Collapse
|
2
|
Wei J, Chen B, Dong J, Wang X, Li Y, Liu Y, Guan W. Salinomycin biosynthesis reversely regulates the β-oxidation pathway in Streptomyces albus by carrying a 3-hydroxyacyl-CoA dehydrogenase gene in its biosynthetic gene cluster. Microb Biotechnol 2022; 15:2890-2904. [PMID: 36099515 PMCID: PMC9733648 DOI: 10.1111/1751-7915.14145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/31/2022] [Indexed: 12/14/2022] Open
Abstract
Streptomyces is well known for synthesis of many biologically active secondary metabolites, such as polyketides and non-ribosomal peptides. Understanding the coupling mechanisms of primary and secondary metabolism can help develop strategies to improve secondary metabolite production in Streptomyces. In this work, Streptomyces albus ZD11, an oil-preferring industrial Streptomyces strain, was proved to have a remarkable capability to generate abundant acyl-CoA precursors for salinomycin biosynthesis with the aid of its enhanced β-oxidation pathway. It was found that the salinomycin biosynthetic gene cluster contains a predicted 3-hydroxyacyl-CoA dehydrogenase (FadB3), which is the third enzyme of β-oxidation cycle. Deletion of fadB3 significantly reduced the production of salinomycin. A variety of experimental evidences showed that FadB3 was mainly involved in the β-oxidation pathway rather than ethylmalonyl-CoA biosynthesis and played a very important role in regulating the rate of β-oxidation in S. albus ZD11. Our findings elucidate an interesting coupling mechanism by which a PKS biosynthetic gene cluster could regulate the β-oxidation pathway by carrying β-oxidation genes, enabling Streptomyces to efficiently synthesize target polyketides and economically utilize environmental nutrients.
Collapse
Affiliation(s)
- Jiaxiu Wei
- The Fourth Affiliated HospitalZhejiang University School of MedicineHangzhouChina,Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic EngineeringHangzhouChina
| | - Binbin Chen
- ZJU‐Hangzhou Global Scientific and Technological Innovation CenterHangzhouChina
| | - Jianxin Dong
- The Fourth Affiliated HospitalZhejiang University School of MedicineHangzhouChina,Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic EngineeringHangzhouChina
| | - Xueyu Wang
- The Fourth Affiliated HospitalZhejiang University School of MedicineHangzhouChina,Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic EngineeringHangzhouChina
| | - Yongquan Li
- The Fourth Affiliated HospitalZhejiang University School of MedicineHangzhouChina,Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic EngineeringHangzhouChina
| | - Yingchun Liu
- Department of ChemistryZhejiang UniversityHangzhouChina
| | - Wenjun Guan
- The Fourth Affiliated HospitalZhejiang University School of MedicineHangzhouChina,Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic EngineeringHangzhouChina
| |
Collapse
|
3
|
Son HF, Ahn JW, Hong J, Seok J, Jin KS, Kim KJ. Crystal structure of multi-functional enzyme FadB from Cupriavidus necator: Non-formation of FadAB complex. Arch Biochem Biophys 2022; 730:109391. [PMID: 36087768 DOI: 10.1016/j.abb.2022.109391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/14/2022] [Accepted: 08/31/2022] [Indexed: 11/17/2022]
Abstract
Cupriavidus necator H16 is a gram-negative chemolithoautotrophic bacterium that has been extensively studied for biosynthesis and biodegradation of polyhydroxyalkanoate (PHA) plastics. To improve our understanding of fatty acid metabolism for PHA production, we determined the crystal structure of multi-functional enoyl-CoA hydratase from Cupriavidus necator H16 (CnFadB). The predicted model of CnFadB created by AlphaFold was used to solve the phase problem during determination of the crystal structure of the protein. The CnFadB structure consists of two distinctive domains, an N-terminal enol-CoA hydratase (ECH) domain and a C-terminal 3-hydroxyacyl-CoA dehydrogenase (HAD) domain, and the substrate- and cofactor-binding modes of these two functional domains were identified. Unlike other known FadB enzymes that exist as dimers complexed with FadA, CnFadB functions as a monomer without forming a complex with CnFadA. Small angle X-ray scattering (SAXS) measurement further proved that CnFadB exists as a monomer in solution. The non-sequential action of FadA and FadB in C. necator appears to affect β-oxidation and PHA synthesis/degradation.
Collapse
Affiliation(s)
- Hyeoncheol Francis Son
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Jae-Woo Ahn
- Postech Biotech Center, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea; Center for Biomolecular Capture Technology, Bio Open Innovation Center, Pohang University of Science and Technology, 47 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Jiyeon Hong
- School of Life Sciences, BK21 Four KNU Creative BioResearch Group, KNU Institute for Microorganisms, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu, 41566, Republic of Korea
| | - Jihye Seok
- School of Life Sciences, BK21 Four KNU Creative BioResearch Group, KNU Institute for Microorganisms, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu, 41566, Republic of Korea
| | - Kyeong Sik Jin
- Pohang Accelerator Laboratory, 80 Jigokro-127-beongil, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Kyung-Jin Kim
- School of Life Sciences, BK21 Four KNU Creative BioResearch Group, KNU Institute for Microorganisms, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu, 41566, Republic of Korea.
| |
Collapse
|
4
|
von Horsten S, Lippert ML, Geisselbrecht Y, Schühle K, Schall I, Essen LO, Heider J. Inactive pseudoenzyme subunits in heterotetrameric BbsCD, a novel short-chain alcohol dehydrogenase involved in anaerobic toluene degradation. FEBS J 2021; 289:1023-1042. [PMID: 34601806 DOI: 10.1111/febs.16216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 12/15/2022]
Abstract
Anaerobic toluene degradation proceeds by fumarate addition to produce (R)-benzylsuccinate as first intermediate, which is further degraded via β-oxidation by five enzymes encoded in the conserved bbs operon. This study characterizes two enzymes of this pathway, (E)-benzylidenesuccinyl-CoA hydratase (BbsH), and (S,R)-2-(α-hydroxybenzyl)succinyl-CoA dehydrogenase (BbsCD) from Thauera aromatica. BbsH, a member of the enoyl-CoA hydratase family, converts (E)-benzylidenesuccinyl-CoA to 2-(α-hydroxybenzyl)succinyl-CoA and was subsequently used in a coupled enzyme assay with BbsCD, which belongs to the short-chain dehydrogenases/reductase (SDR) family. The BbsCD crystal structure shows a C2-symmetric heterotetramer consisting of BbsC2 and BbsD2 dimers. BbsD subunits are catalytically active and capable of binding NAD+ and substrate, whereas BbsC subunits represent built-in pseudoenzyme moieties lacking all motifs of the SDR family required for substrate binding or catalysis. Molecular modeling studies predict that the active site of BbsD is specific for conversion of the (S,R)-diastereomer of 2-(α-hydroxybenzyl)succinyl-CoA to (S)-2-benzoylsuccinyl-CoA by hydride transfer to the re-face of nicotinamide adenine dinucleotide (NAD)+ . Furthermore, BbsC subunits are not engaged in substrate binding and merely serve as scaffold for the BbsD dimer. BbsCD represents a novel clade of related enzymes within the SDR family, which adopt a heterotetrameric architecture and catalyze the β-oxidation of aromatic succinate adducts.
Collapse
Affiliation(s)
| | | | | | - Karola Schühle
- Department of Biology, Philipps-Universität, Marburg, Germany
| | - Iris Schall
- Department of Biology, Philipps-Universität, Marburg, Germany
| | | | - Johann Heider
- Department of Biology, Philipps-Universität, Marburg, Germany
| |
Collapse
|
5
|
Liu L, Schubert DM, Könneke M, Berg IA. ( S)-3-Hydroxybutyryl-CoA Dehydrogenase From the Autotrophic 3-Hydroxypropionate/4-Hydroxybutyrate Cycle in Nitrosopumilus maritimus. Front Microbiol 2021; 12:712030. [PMID: 34290692 PMCID: PMC8287830 DOI: 10.3389/fmicb.2021.712030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/11/2021] [Indexed: 11/18/2022] Open
Abstract
Ammonia-oxidizing archaea of the phylum Thaumarchaeota are among the most abundant organisms that exert primary control of oceanic and soil nitrification and are responsible for a large part of dark ocean primary production. They assimilate inorganic carbon via an energetically efficient version of the 3-hydroxypropionate/4-hydroxybutyrate cycle. In this cycle, acetyl-CoA is carboxylated to succinyl-CoA, which is then converted to two acetyl-CoA molecules with 4-hydroxybutyrate as the key intermediate. This conversion includes the (S)-3-hydroxybutyryl-CoA dehydrogenase reaction. Here, we heterologously produced the protein Nmar_1028 catalyzing this reaction in thaumarchaeon Nitrosopumilus maritimus, characterized it biochemically and performed its phylogenetic analysis. This NAD-dependent dehydrogenase is highly active with its substrate, (S)-3-hydroxybutyryl-CoA, and its low Km value suggests that the protein is adapted to the functioning in the 3-hydroxypropionate/4-hydroxybutyrate cycle. Nmar_1028 is homologous to the dehydrogenase domain of crotonyl-CoA hydratase/(S)-3-hydroxybutyryl-CoA dehydrogenase that is present in many Archaea. Apparently, the loss of the dehydratase domain of the fusion protein in the course of evolution was accompanied by lateral gene transfer of 3-hydroxypropionyl-CoA dehydratase/crotonyl-CoA hydratase from Bacteria. Although (S)-3-hydroxybutyryl-CoA dehydrogenase studied here is neither unique nor characteristic for the HP/HB cycle, Nmar_1028 appears to be the only (S)-3-hydroxybutyryl-CoA dehydrogenase in N. maritimus and is thus essential for the functioning of the 3-hydroxypropionate/4-hydroxybutyrate cycle and for the biology of this important marine archaeon.
Collapse
Affiliation(s)
- Li Liu
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
| | - Daniel M Schubert
- Department of Microbiology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Martin Könneke
- Marine Archaea Group, MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.,Benthic Microbiology, Institute for Chemistry and Biology of the Marine Environments, University of Oldenburg, Oldenburg, Germany
| | - Ivan A Berg
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
| |
Collapse
|
6
|
Orrego AH, Andrés-Sanz D, Velasco-Lozano S, Sanchez-Costa M, Berenguer J, Guisan JM, Rocha-Martin J, López-Gallego F. Self-sufficient asymmetric reduction of β-ketoesters catalysed by a novel and robust thermophilic alcohol dehydrogenase co-immobilised with NADH. Catal Sci Technol 2021; 11:3217-3230. [PMID: 34094502 PMCID: PMC8111925 DOI: 10.1039/d1cy00268f] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 02/25/2021] [Indexed: 12/04/2022]
Abstract
β-Hydroxyesters are essential building blocks utilised by the pharmaceutical and food industries in the synthesis of functional products. Beyond the conventional production methods based on chemical catalysis or whole-cell synthesis, the asymmetric reduction of β-ketoesters with cell-free enzymes is gaining relevance. To this end, a novel thermophilic (S)-3-hydroxybutyryl-CoA dehydrogenase from Thermus thermophilus HB27 (Tt27-HBDH) has been expressed, purified and biochemically characterised, determining its substrate specificity towards β-ketoesters and its dependence on NADH as a cofactor. The immobilization of Tt27-HBDH on agarose macroporous beads and its subsequent coating with polyethyleneimine has been found the best strategy to increase the stability and workability of the heterogeneous biocatalyst. Furthermore, we have embedded NADH in the cationic layer attached to the porous surface of the carrier. Since Tt27-HBDH catalyses cofactor recycling through 2-propanol oxidation, we achieve a self-sufficient heterogeneous biocatalyst where NADH is available for the immobilised enzymes but its lixiviation to the reaction bulk is avoided. Taking advantage of the autofluorescence of NADH, we demonstrate the activity of the enzyme towards the immobilised cofactor through single-particle analysis. Finally, we tested the operational stability in the asymmetric reduction of β-ketoesters in batch, succeeding in the reuse of both the enzyme and the co-immobilised cofactor up to 10 reaction cycles.
Collapse
Affiliation(s)
- Alejandro H Orrego
- Department of Biocatalysis, Institute of Catalysis and Petrochemistry (ICP), CSIC Campus UAM, Cantoblanco 28049 Madrid Spain
- Department of Molecular Biology, Universidad Autónoma de Madrid, Center for Molecular Biology Severo-Ochoa (UAM-CSIC) Nicolás Cabrera 1 28049 Madrid Spain
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA) Paseo de Miramón 182 Donostia San Sebastián Spain
| | - Daniel Andrés-Sanz
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA) Paseo de Miramón 182 Donostia San Sebastián Spain
| | - Susana Velasco-Lozano
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA) Paseo de Miramón 182 Donostia San Sebastián Spain
| | - Mercedes Sanchez-Costa
- Department of Molecular Biology, Universidad Autónoma de Madrid, Center for Molecular Biology Severo-Ochoa (UAM-CSIC) Nicolás Cabrera 1 28049 Madrid Spain
| | - José Berenguer
- Department of Molecular Biology, Universidad Autónoma de Madrid, Center for Molecular Biology Severo-Ochoa (UAM-CSIC) Nicolás Cabrera 1 28049 Madrid Spain
| | - José M Guisan
- Department of Biocatalysis, Institute of Catalysis and Petrochemistry (ICP), CSIC Campus UAM, Cantoblanco 28049 Madrid Spain
| | - Javier Rocha-Martin
- Department of Biocatalysis, Institute of Catalysis and Petrochemistry (ICP), CSIC Campus UAM, Cantoblanco 28049 Madrid Spain
| | - Fernando López-Gallego
- Heterogeneous Biocatalysis Laboratory, Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA) Paseo de Miramón 182 Donostia San Sebastián Spain
- IKERBASQUE, Basque Foundation for Science María Díaz de Haro 3 48013 Bilbao Spain
| |
Collapse
|
7
|
Revealing the Metabolic Flexibility of " Candidatus Accumulibacter phosphatis" through Redox Cofactor Analysis and Metabolic Network Modeling. Appl Environ Microbiol 2020; 86:AEM.00808-20. [PMID: 33008826 DOI: 10.1128/aem.00808-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 09/21/2020] [Indexed: 12/27/2022] Open
Abstract
Environmental fluctuations in the availability of nutrients lead to intricate metabolic strategies. "Candidatus Accumulibacter phosphatis," a polyphosphate-accumulating organism (PAO) responsible for enhanced biological phosphorus removal (EBPR) from wastewater treatment systems, is prevalent in aerobic/anaerobic environments. While the overall metabolic traits of these bacteria are well described, the nonavailability of isolates has led to controversial conclusions on the metabolic pathways used. In this study, we experimentally determined the redox cofactor preferences of different oxidoreductases in the central carbon metabolism of a highly enriched "Ca Accumulibacter phosphatis" culture. Remarkably, we observed that the acetoacetyl coenzyme A reductase engaged in polyhydroxyalkanoate (PHA) synthesis is NADH preferring instead of showing the generally assumed NADPH dependency. This allows rethinking of the ecological role of PHA accumulation as a fermentation product under anaerobic conditions and not just a stress response. Based on previously published metaomics data and the results of enzymatic assays, a reduced central carbon metabolic network was constructed and used for simulating different metabolic operating modes. In particular, scenarios with different acetate-to-glycogen consumption ratios were simulated, which demonstrated optima using different combinations of glycolysis, glyoxylate shunt, or branches of the tricarboxylic acid (TCA) cycle. Thus, optimal metabolic flux strategies will depend on the environment (acetate uptake) and on intracellular storage compound availability (polyphosphate/glycogen). This NADH-related metabolic flexibility is enabled by the NADH-driven PHA synthesis. It allows for maintaining metabolic activity under various environmental substrate conditions, with high carbon conservation and lower energetic costs than for NADPH-dependent PHA synthesis. Such (flexible) metabolic redox coupling can explain the competitiveness of PAOs under oxygen-fluctuating environments.IMPORTANCE Here, we demonstrate how microbial storage metabolism can adjust to a wide range of environmental conditions. Such flexibility generates a selective advantage under fluctuating environmental conditions. It can also explain the different observations reported in PAO literature, including the capacity of "Ca Accumulibacter phosphatis" to act like glycogen-accumulating organisms (GAOs). These observations stem from slightly different experimental conditions, and controversy arises only when one assumes that metabolism can operate only in a single mode. Furthermore, we also show how the study of metabolic strategies is possible when combining omics data with functional cofactor assays and modeling. Genomic information can only provide the potential of a microorganism. The environmental context and other complementary approaches are still needed to study and predict the functional expression of such metabolic potential.
Collapse
|
8
|
Takenoya M, Taguchi S, Yajima S. Crystal structure and kinetic analyses of a hexameric form of (S)-3-hydroxybutyryl-CoA dehydrogenase from Clostridium acetobutylicum. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2018; 74:733-740. [PMID: 30387779 DOI: 10.1107/s2053230x18014814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/19/2018] [Indexed: 11/11/2022]
Abstract
(S)-3-Hydroxybutyryl-CoA dehydrogenase (HBD) has been gaining increased attention recently as it is a key enzyme in the enantiomeric formation of (S)-3-hydroxybutyryl-CoA [(S)-3HB-CoA]. It converts acetoacetyl-CoA to (S)-3HB-CoA in the synthetic metabolic pathway. (S)-3HB-CoA is further modified to form (S)-3-hydroxybutyrate, which is a source of biodegradable polymers. During the course of a study to develop biodegradable polymers, attempts were made to determine the crystal structure of HBD from Clostridium acetobutylicum (CacHBD), and the crystal structures of both apo and NAD+-bound forms of CacHBD were determined. The crystals belonged to different space groups: P212121 and P21. However, both structures adopted a hexamer composed of three dimers in the asymmetric unit, and this oligomerization was additionally confirmed by gel-filtration column chromatography. Furthermore, to investigate the catalytic residues of CacHBD, the enzymatic activities of the wild type and of three single-amino-acid mutants were analyzed, in which the Ser, His and Asn residues that are conserved in the HBDs from C. acetobutylicum, C. butyricum and Ralstonia eutropha, as well as in the L-3-hydroxyacyl-CoA dehydrogenases from Homo sapiens and Escherichia coli, were substituted by alanines. The S117A and N188A mutants abolished the activity, while the H138A mutant showed a slightly lower Km value and a significantly lower kcat value than the wild type. Therefore, in combination with the crystal structures, it was shown that His138 is involved in catalysis and that Ser117 and Asn188 may be important for substrate recognition to place the keto group of the substrate in the correct position for reaction.
Collapse
Affiliation(s)
- Mihoko Takenoya
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Seiichi Taguchi
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Shunsuke Yajima
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| |
Collapse
|
9
|
Segawa M, Wen C, Orita I, Nakamura S, Fukui T. Two NADH-dependent (S)-3-hydroxyacyl-CoA dehydrogenases from polyhydroxyalkanoate-producing Ralstonia eutropha. J Biosci Bioeng 2018; 127:294-300. [PMID: 30243533 DOI: 10.1016/j.jbiosc.2018.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/20/2018] [Accepted: 08/22/2018] [Indexed: 12/28/2022]
Abstract
Ralstonia eutropha H16 contains both NADH- and NADPH-dependent reduction activities to acetoacetyl-CoA, and the NADPH-dependent activity is mediated by PhaB paralogs with (R)-stereospecificity providing (R)-3-hydroxybutyryl (3HB)-CoA monomer for poly((R)-3-hydroxybutyrate) synthesis. In contrast, the gene encoding the NADH-dependent enzyme has not been identified to date. This study focused on the NADH-dependent dehydrogenase with (S)-stereospecificity in R. eutropha, as the (S)-specific reduction of acetoacetyl-CoA potentially competed with the polyester biosynthesis via (R)-3HB-CoA. The NADH-dependent reduction activity decreased to one-half when the gene for H16_A0282 (PaaH1), one of two homologs of clostridial NADH-3HB-CoA dehydrogenase, was deleted. The enzyme responsible for the remaining activity was partially purified and identified as H16_A0602 (Had) belonging to a different family from PaaH1. Gene disruption analysis elucidated that most of the NADH-dependent activity was mediated by PaaH1 and Had. The kinetic analysis using the recombinant enzymes indicated that PaaH1 and Had were both NADH-dependent 3-hydroxyacyl-CoA dehydrogenases with rather broad substrate specificity to 3-oxoacyl-CoAs of C4 to C8. The deletion of had in the R. eutropha strain previously engineered for biosynthesis of poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) led to decrease in the C6 composition of the copolyester synthesized from soybean oil, suggesting the role of Had in (S)-specific reduction of 3-oxohexanoyl-CoA with reverse β-oxidation direction. Crotonase ((S)-specific enoyl-CoA hydratase) in R. eutropha H16 was also partially purified and identified as H16_A3307.
Collapse
Affiliation(s)
- Mutsumi Segawa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Cheng Wen
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Izumi Orita
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Satoshi Nakamura
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Toshiaki Fukui
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
| |
Collapse
|
10
|
Sagong HY, Son HF, Choi SY, Lee SY, Kim KJ. Structural Insights into Polyhydroxyalkanoates Biosynthesis. Trends Biochem Sci 2018; 43:790-805. [PMID: 30139647 DOI: 10.1016/j.tibs.2018.08.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/27/2018] [Accepted: 08/04/2018] [Indexed: 12/25/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are diverse biopolyesters produced by numerous microorganisms and have attracted much attention as a substitute for petroleum-based polymers. Despite several decades of study, the detailed molecular mechanisms of PHA biosynthesis have remained unknown due to the lack of structural information on the key PHA biosynthetic enzyme PHA synthase. The recently determined crystal structure of PHA synthase, together with the structures of acetyl-coenzyme A (CoA) acetyltransferase and reductase, have changed this situation. Structural and biochemical studies provided important clues for the molecular mechanisms of each enzyme as well as the overall mechanism of PHA biosynthesis from acetyl-CoA. This new information and knowledge is expected to facilitate production of designed novel PHAs and also enhanced production of PHAs.
Collapse
Affiliation(s)
- Hye-Young Sagong
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Hyeoncheol Francis Son
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - So Young Choi
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea.
| |
Collapse
|
11
|
(S)-3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase (FadB') from fatty acid degradation operon of Ralstonia eutropha H16. AMB Express 2014; 4:69. [PMID: 25401070 PMCID: PMC4230905 DOI: 10.1186/s13568-014-0069-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/13/2014] [Indexed: 11/12/2022] Open
Abstract
In this study (S)-3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase (H16_A0461/FadB’, gene ID: 4247876) from one of two active fatty acid degradation operons of Ralstonia eutropha H16 has been heterologously expressed in Escherichia coli, purified as protein possessing a His-Tag and initially characterized. FadB’ is an enzyme with two catalytic domains exhibiting a single monomeric structure and possessing a molecular weight of 86 kDa. The C-terminal part of the enzyme harbors enoyl-CoA hydratase activity and is able to convert trans-crotonyl-CoA to 3-hydroxybutyryl-CoA. The N-terminal part of FadB’ comprises an NAD+ binding site and is responsible for 3-hydroxyacyl-CoA dehydrogenase activity converting (S)-3-hydroxybutyryl-CoA to acetoacetyl-CoA. Enoyl-CoA hydratase activity was detected spectrophotometrically with trans-crotonyl-CoA. (S)-3-Hydroxyacyl-CoA dehydrogenase activity was measured in both directions with acetoacetyl-CoA and 3-hydroxybutyryl-CoA. FadB’ was found to be strictly stereospecific to (S)-3-hydroxybutyryl-CoA and to prefer NAD+. The Km value for acetoacetyl-CoA was 48 μM and Vmax 149 μmol mg−1 min−1. NADP(H) was utilized at a rate of less than 10% in comparison to activity with NAD(H). FadB’ exhibited optimal activity at pH 6–7 and the activity decreased at alkaline and acidic pH values. Acetyl-CoA, propionyl-CoA and CoA were found to have an inhibitory effect on FadB’. This study is a first report on biochemical properties of purified (S)-stereospecific 3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase with the inverted domain order from R. eutropha H16. In addition to fundamental information about FadB’ and fatty acid metabolism, FadB’ might be also interesting for biotechnological applications.
Collapse
|