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Bleem AC, Kuatsjah E, Johnsen J, Mohamed ET, Alexander WG, Kellermyer ZA, Carroll AL, Rossi R, Schlander IB, Peabody V GL, Guss AM, Feist AM, Beckham GT. Evolution and engineering of pathways for aromatic O-demethylation in Pseudomonas putida KT2440. Metab Eng 2024; 84:145-157. [PMID: 38936762 DOI: 10.1016/j.ymben.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/17/2024] [Accepted: 06/24/2024] [Indexed: 06/29/2024]
Abstract
Biological conversion of lignin from biomass offers a promising strategy for sustainable production of fuels and chemicals. However, aromatic compounds derived from lignin commonly contain methoxy groups, and O-demethylation of these substrates is often a rate-limiting reaction that influences catabolic efficiency. Several enzyme families catalyze aromatic O-demethylation, but they are rarely compared in vivo to determine an optimal biocatalytic strategy. Here, two pathways for aromatic O-demethylation were compared in Pseudomonas putida KT2440. The native Rieske non-heme iron monooxygenase (VanAB) and, separately, a heterologous tetrahydrofolate-dependent demethylase (LigM) were constitutively expressed in P. putida, and the strains were optimized via adaptive laboratory evolution (ALE) with vanillate as a model substrate. All evolved strains displayed improved growth phenotypes, with the evolved strains harboring the native VanAB pathway exhibiting growth rates ∼1.8x faster than those harboring the heterologous LigM pathway. Enzyme kinetics and transcriptomics studies investigated the contribution of selected mutations toward enhanced utilization of vanillate. The VanAB-overexpressing strains contained the most impactful mutations, including those in VanB, the reductase for vanillate O-demethylase, PP_3494, a global regulator of vanillate catabolism, and fghA, involved in formaldehyde detoxification. These three mutations were combined into a single strain, which exhibited approximately 5x faster vanillate consumption than the wild-type strain in the first 8 h of cultivation. Overall, this study illuminates the details of vanillate catabolism in the context of two distinct enzymatic mechanisms, yielding a platform strain for efficient O-demethylation of lignin-related aromatic compounds to value-added products.
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Affiliation(s)
- Alissa C Bleem
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Eugene Kuatsjah
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Josefin Johnsen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Elsayed T Mohamed
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - William G Alexander
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Biosciences Division, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN, USA
| | - Zoe A Kellermyer
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Austin L Carroll
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Biosciences Division, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN, USA
| | - Riccardo Rossi
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark; Department of Bioengineering, University of California, San Diego, CA, USA
| | - Ian B Schlander
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - George L Peabody V
- Biosciences Division, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN, USA
| | - Adam M Guss
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Biosciences Division, Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN, USA
| | - Adam M Feist
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark; Joint BioEnergy Institute, Emeryville, CA, USA; Department of Bioengineering, University of California, San Diego, CA, USA.
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
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Li M, Miao H, Li Y, Wang F, Xu J. Protein Engineering of an Artificial P450BM3 Peroxygenase System Enables Highly Selective O-Demethylation of Lignin Monomers. Molecules 2022; 27:molecules27103120. [PMID: 35630597 PMCID: PMC9143554 DOI: 10.3390/molecules27103120] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/03/2022] [Accepted: 05/11/2022] [Indexed: 02/01/2023] Open
Abstract
The O-demethylation of lignin monomers, which has drawn substantial attention recently, is critical for the formation of phenols from aromatic ethers. The P450BM3 peroxygenase system was recently found to enable the O-demethylation of different aromatic ethers with the assistance of dual-functional small molecules (DFSM), but these prepared mutants only have either moderate O-demethylation activity or moderate selectivity, which hinders their further application. In this study, we improve the system by introducing different amino acids into the active site of P450BM3, and these amino acids with different side chains impacted the catalytic ability of enzymes due to their differences in size, polarity, and hydrophobicity. Among the prepared mutants, the combination of V78A/F87A/T268I/A264G and Im-C6-Phe efficiently catalyzed the O-demethylation of guaiacol (TON = 839) with 100% selectivity. Compared with NADPH-dependent systems, we offer an economical and practical bioconversion avenue.
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Affiliation(s)
- Maosheng Li
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China;
- Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Lab for Marine Drugs and Byproducts of Pilot National Lab for Marine Science and Technology, Qingdao 266071, China; (H.M.); (Y.L.); (F.W.)
| | - Hengmin Miao
- Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Lab for Marine Drugs and Byproducts of Pilot National Lab for Marine Science and Technology, Qingdao 266071, China; (H.M.); (Y.L.); (F.W.)
| | - Yanqing Li
- Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Lab for Marine Drugs and Byproducts of Pilot National Lab for Marine Science and Technology, Qingdao 266071, China; (H.M.); (Y.L.); (F.W.)
| | - Fang Wang
- Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Lab for Marine Drugs and Byproducts of Pilot National Lab for Marine Science and Technology, Qingdao 266071, China; (H.M.); (Y.L.); (F.W.)
| | - Jiakun Xu
- Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Lab for Marine Drugs and Byproducts of Pilot National Lab for Marine Science and Technology, Qingdao 266071, China; (H.M.); (Y.L.); (F.W.)
- Correspondence: ; Tel.: +86-13869828530
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Kuatsjah E, Chan ACK, Katahira R, Haugen SJ, Beckham GT, Murphy MEP, Eltis LD. Structural and functional analysis of lignostilbene dioxygenases from Sphingobium sp. SYK-6. J Biol Chem 2021; 296:100758. [PMID: 33965373 PMCID: PMC8191317 DOI: 10.1016/j.jbc.2021.100758] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 04/28/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022] Open
Abstract
Lignostilbene-α,β-dioxygenases (LSDs) are iron-dependent oxygenases involved in the catabolism of lignin-derived stilbenes. Sphingobium sp. SYK-6 contains eight LSD homologs with undetermined physiological roles. To investigate which homologs are involved in the catabolism of dehydrodiconiferyl alcohol (DCA), derived from β-5 linked lignin subunits, we heterologously produced the enzymes and screened their activities in lysates. The seven soluble enzymes all cleaved lignostilbene, but only LSD2, LSD3, and LSD4 exhibited high specific activity for 3-(4-hydroxy-3-(4-hydroxy-3-methoxystyryl)-5-methoxyphenyl) acrylate (DCA-S) relative to lignostilbene. LSD4 catalyzed the cleavage of DCA-S to 5-formylferulate and vanillin and cleaved lignostilbene and DCA-S (∼106 M−1 s−1) with tenfold greater specificity than pterostilbene and resveratrol. X-ray crystal structures of native LSD4 and the catalytically inactive cobalt-substituted Co-LSD4 at 1.45 Å resolution revealed the same fold, metal ion coordination, and edge-to-edge dimeric structure as observed in related enzymes. Key catalytic residues, Phe-59, Tyr-101, and Lys-134, were also conserved. Structures of Co-LSD4·vanillin, Co-LSD4·lignostilbene, and Co-LSD4·DCA-S complexes revealed that Ser-283 forms a hydrogen bond with the hydroxyl group of the ferulyl portion of DCA-S. This residue is conserved in LSD2 and LSD4 but is alanine in LSD3. Substitution of Ser-283 with Ala minimally affected the specificity of LSD4 for either lignostilbene or DCA-S. By contrast, substitution with phenylalanine, as occurs in LSD5 and LSD6, reduced the specificity of the enzyme for both substrates by an order of magnitude. This study expands our understanding of an LSD critical to DCA catabolism as well as the physiological roles of other LSDs and their determinants of substrate specificity.
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Affiliation(s)
- Eugene Kuatsjah
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge Tennessee, USA
| | - Anson C K Chan
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Rui Katahira
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Stefan J Haugen
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge Tennessee, USA
| | - Michael E P Murphy
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; BioProducts Institute, The University of British Columbia, Vancouver, Canada
| | - Lindsay D Eltis
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; BioProducts Institute, The University of British Columbia, Vancouver, Canada.
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Jenkins MC, Lutz S. Encapsulin Nanocontainers as Versatile Scaffolds for the Development of Artificial Metabolons. ACS Synth Biol 2021; 10:857-869. [PMID: 33769792 DOI: 10.1021/acssynbio.0c00636] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The construction of non-native biosynthetic pathways represents a powerful, modular strategy for the production of valuable synthons and fine chemicals. Accordingly, artificially affixing enzymes that catalyze sequential reactions onto DNAs, proteins, or synthetic scaffolds has proven to be an effective route for generating de novo metabolons with novel functionalities and superior efficiency. In recent years, nanoscale microbial compartments known as encapsulins have emerged as a class of robust and highly engineerable proteinaceous containers with myriad applications in biotechnology and synthetic biology. Herein we report the concurrent surface functionalization and internal packaging of encapsulins from Thermotoga maritima to generate a catalytically competent two-enzyme metabolon. Encapsulins were engineered to covalently sequester up to 60 copies of a dihydrofolate reductase (DHFR) enzyme variant on their exterior surfaces using the SpyCatcher bioconjugation system, while their lumens were packaged with a tetrahydrofolate-dependent demethylase enzyme using short peptide affinity tags abstracted from the encapsulin's native protein cargo. Successful cross-talk between the two colocalized enzymes was confirmed as tetrahydrofolate produced by externally tethered DHFR was capable of driving the demethylation of a lignin-derived aryl substrate by packaged demethylases, albeit slowly. The subsequent introduction of a previously reported pore-enlarging deletion in the encapsulin shell was shown to enhance metabolite exchange such that the encapsulin-based metabolon functioned at speeds equivalent to those of the two enzymes freely dispersed in solution. Our work thus further emphasizes the engineerability of encapsulins and their potential use as flexile scaffolds for biocatalytic applications.
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Affiliation(s)
- Matthew C. Jenkins
- Department of Chemistry, Emory University, Atlanta, Georgia 30084, United States
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30306, United States
| | - Stefan Lutz
- Department of Chemistry, Emory University, Atlanta, Georgia 30084, United States
- Codexis Inc., 200 Penobscot Drive, Redwood City, California 94063, United States
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Cheng Q, DeYonker NJ. QM-Cluster Model Study of the Guaiacol Hydrogen Atom Transfer and Oxygen Rebound with Cytochrome P450 Enzyme GcoA. J Phys Chem B 2021; 125:3296-3306. [PMID: 33784103 DOI: 10.1021/acs.jpcb.0c10761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The key step of the O-demethylation of guaiacol by GcoA of the cytochrome P450-reductase pair was studied with DFT using two 10-residue and three 15-residue QM-cluster models. For each model, two reaction pathways were examined, beginning with a different guaiacol orientation. Based on this study, His354, Phe349, Glu249, and Pro250 residues were found to be important for keeping the heme in a planar geometry throughout the reaction. Val241 and Gly245 residues were needed in the QM-cluster models to provide the hydrophobic pocket for an appropriate guaiacol pose in the reaction. The aromatic triad Phe75, Phe169, and Phe395 may be necessary to facilitate guaiacol migrating into the enzyme active site, but it does not qualitatively affect kinetics and thermodynamics of the proposed mechanism. All QM-cluster models created by RINRUS agree very well with previous experimental work. This study provides details for better understanding enzymatic O-demethylation of lignins to form catechol derivatives by GcoA.
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Affiliation(s)
- Qianyi Cheng
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
| | - Nathan J DeYonker
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
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Venkatesagowda B, Dekker RFH. Microbial demethylation of lignin: Evidence of enzymes participating in the removal of methyl/methoxyl groups. Enzyme Microb Technol 2021; 147:109780. [PMID: 33992403 DOI: 10.1016/j.enzmictec.2021.109780] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 02/27/2021] [Accepted: 03/11/2021] [Indexed: 11/30/2022]
Abstract
Lignin is an abundant natural plant aromatic biopolymer containing various functional groups that can be exploited for activating lignin for potential commercial applications. Applications are hindered due to the presence of a high content of methyl/methoxyl groups that affects reactiveness. Various chemical and enzymatic approaches have been investigated to increase the functionality in transforming lignin. Among these is demethylation/demethoxylation, which increases the potential numbers of vicinal hydroxyl groups for applications as phenol-formaldehyde resins. Although the chemical route to lignin demethylation is well-studied, the biological route is still poorly explored. Bacteria and fungi have the ability to demethylate lignin and lignin-related compounds. Considering that appropriate microorganisms possess the biochemical machinery to demethylate lignin by cleaving O-methyl groups liberating methanol, and modify lignin by increasing the vicinal diol content that allows lignin to substitute for phenol in organic polymer syntheses. Certain bacteria through the actions of specific O-demethylases can modify various lignin-related compounds generating vicinal diols and liberating methanol or formaldehyde as end-products. The enzymes include: cytochrome P450-aryl-O-demethylase, monooxygenase, veratrate 3-O-demethylase, DDVA O-demethylase (LigX; lignin-related biphenyl 5,5'-dehydrodivanillate (DDVA)), vanillate O-demethylase, syringate O-demethylase, and tetrahydrofolate-dependent-O-demethylase. Although, the fungal counterparts have not been investigated in depth as in bacteria, O-demethylases, nevertheless, have been reported in demethylating various lignin substrates providing evidence of a fungal enzyme system. Few fungi appear to have the ability to secrete O-demethylases. The fungi can mediate lignin demethylation enzymatically (laccase, lignin peroxidase, manganese peroxidase, O-demethylase), or non-enzymatically in brown-rot fungi through the Fenton reaction. This review discusses details on the aspects of microbial (bacterial and fungal) demethylation of lignins and lignin-model compounds and provides evidence of enzymes identified as specific O-demethylases involved in demethylation.
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Affiliation(s)
- Balaji Venkatesagowda
- Biorefining Research Institute, Lakehead University, Thunder Bay, Ontario, P7B 5E1, Canada.
| | - Robert F H Dekker
- Biorefining Research Institute, Lakehead University, Thunder Bay, Ontario, P7B 5E1, Canada; Universidade Tecnológica Federal do Paraná, Programa de Pós-Graduação em Engenharia Ambiental, Câmpus Londrina, CEP: 86036-370, Londrina, PR, Brazil.
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Identifying metabolic pathway intermediates that modulate the gallate dioxygenase (DesB) from Sphingobium sp. strain SYK-6. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Vigouroux A, Meyer T, Naretto A, Legrand P, Aumont-Nicaise M, Di Cicco A, Renoud S, Doré J, Lévy D, Vial L, Lavire C, Moréra S. Characterization of the first tetrameric transcription factor of the GntR superfamily with allosteric regulation from the bacterial pathogen Agrobacterium fabrum. Nucleic Acids Res 2021; 49:529-546. [PMID: 33313837 PMCID: PMC7797058 DOI: 10.1093/nar/gkaa1181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/12/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
A species-specific region, denoted SpG8-1b allowing hydroxycinnamic acids (HCAs) degradation is important for the transition between the two lifestyles (rhizospheric versus pathogenic) of the plant pathogen Agrobacterium fabrum. Indeed, HCAs can be either used as trophic resources and/or as induced-virulence molecules. The SpG8-1b region is regulated by two transcriptional regulators, namely, HcaR (Atu1422) and Atu1419. In contrast to HcaR, Atu1419 remains so far uncharacterized. The high-resolution crystal structures of two fortuitous citrate complexes, two DNA complexes and the apoform revealed that the tetrameric Atu1419 transcriptional regulator belongs to the VanR group of Pfam PF07729 subfamily of the large GntR superfamily. Until now, GntR regulators were described as dimers. Here, we showed that Atu1419 represses three genes of the HCAs catabolic pathway. We characterized both the effector and DNA binding sites and identified key nucleotides in the target palindrome. From promoter activity measurement using defective gene mutants, structural analysis and gel-shift assays, we propose N5,N10-methylenetetrahydrofolate as the effector molecule, which is not a direct product/substrate of the HCA degradation pathway. The Zn2+ ion present in the effector domain has both a structural and regulatory role. Overall, our work shed light on the allosteric mechanism of transcription employed by this GntR repressor.
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Affiliation(s)
- Armelle Vigouroux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Thibault Meyer
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Anaïs Naretto
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France
| | - Magali Aumont-Nicaise
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Aurélie Di Cicco
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Sébastien Renoud
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Jeanne Doré
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Daniel Lévy
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Ludovic Vial
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Céline Lavire
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Solange Moréra
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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Characterization of alkylguaiacol-degrading cytochromes P450 for the biocatalytic valorization of lignin. Proc Natl Acad Sci U S A 2020; 117:25771-25778. [PMID: 32989155 DOI: 10.1073/pnas.1916349117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytochrome P450 enzymes have tremendous potential as industrial biocatalysts, including in biological lignin valorization. Here, we describe P450s that catalyze the O-demethylation of lignin-derived guaiacols with different ring substitution patterns. Bacterial strains Rhodococcus rhodochrous EP4 and Rhodococcus jostii RHA1 both utilized alkylguaiacols as sole growth substrates. Transcriptomics of EP4 grown on 4-propylguaiacol (4PG) revealed the up-regulation of agcA, encoding a CYP255A1 family P450, and the aph genes, previously shown to encode a meta-cleavage pathway responsible for 4-alkylphenol catabolism. The function of the homologous pathway in RHA1 was confirmed: Deletion mutants of agcA and aphC, encoding the meta-cleavage alkylcatechol dioxygenase, grew on guaiacol but not 4PG. By contrast, deletion mutants of gcoA and pcaL, encoding a CYP255A2 family P450 and an ortho-cleavage pathway enzyme, respectively, grew on 4-propylguaiacol but not guaiacol. CYP255A1 from EP4 catalyzed the O-demethylation of 4-alkylguaiacols to 4-alkylcatechols with the following apparent specificities (k cat/K M): propyl > ethyl > methyl > guaiacol. This order largely reflected AgcA's binding affinities for the different guaiacols and was the inverse of GcoAEP4's specificities. The biocatalytic potential of AgcA was demonstrated by the ability of EP4 to grow on lignin-derived products obtained from the reductive catalytic fractionation of corn stover, depleting alkylguaiacols and alkylphenols. By identifying related P450s with complementary specificities for lignin-relevant guaiacols, this study facilitates the design of these enzymes for biocatalytic applications. We further demonstrated that the metabolic fate of the guaiacol depends on its substitution pattern, a finding that has significant implications for engineering biocatalysts to valorize lignin.
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Hu D, Gao YH, Yao XS, Gao H. Recent advances in dissecting the demethylation reactions in natural product biosynthesis. Curr Opin Chem Biol 2020; 59:47-53. [PMID: 32460136 DOI: 10.1016/j.cbpa.2020.04.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 10/24/2022]
Abstract
Demethylation is a chemical process widely distributed in nature to remove a methyl group from an organic molecule, which is a key aspect of diverse biological processes including biosynthesis of natural products, degradation of plant biomass and epigenetic regulation. This process is facilitated by diverse demethylases via distinct mechanisms. Recent studies have disclosed some novel demethylation reactions as well as their underlying demethylases in the biosynthesis of bacterial sterols, fungal terpenoids, and plant alkaloids. This article focuses on current advances in dissecting the demethylation reactions in biosynthesis of natural products and aims to point out the enzymatic mechanisms, which will further enhance our knowledge and understanding of demethylation process in nature.
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Affiliation(s)
- Dan Hu
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, People's Republic of China.
| | - Yao-Hui Gao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, People's Republic of China
| | - Xin-Sheng Yao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, People's Republic of China
| | - Hao Gao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, People's Republic of China.
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Enabling microbial syringol conversion through structure-guided protein engineering. Proc Natl Acad Sci U S A 2019; 116:13970-13976. [PMID: 31235604 PMCID: PMC6628648 DOI: 10.1073/pnas.1820001116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbial conversion of aromatic compounds is an emerging and promising strategy for valorization of the plant biopolymer lignin. A critical and often rate-limiting reaction in aromatic catabolism is O-aryl-demethylation of the abundant aromatic methoxy groups in lignin to form diols, which enables subsequent oxidative aromatic ring-opening. Recently, a cytochrome P450 system, GcoAB, was discovered to demethylate guaiacol (2-methoxyphenol), which can be produced from coniferyl alcohol-derived lignin, to form catechol. However, native GcoAB has minimal ability to demethylate syringol (2,6-dimethoxyphenol), the analogous compound that can be produced from sinapyl alcohol-derived lignin. Despite the abundance of sinapyl alcohol-based lignin in plants, no pathway for syringol catabolism has been reported to date. Here we used structure-guided protein engineering to enable microbial syringol utilization with GcoAB. Specifically, a phenylalanine residue (GcoA-F169) interferes with the binding of syringol in the active site, and on mutation to smaller amino acids, efficient syringol O-demethylation is achieved. Crystallography indicates that syringol adopts a productive binding pose in the variant, which molecular dynamics simulations trace to the elimination of steric clash between the highly flexible side chain of GcoA-F169 and the additional methoxy group of syringol. Finally, we demonstrate in vivo syringol turnover in Pseudomonas putida KT2440 with the GcoA-F169A variant. Taken together, our findings highlight the significant potential and plasticity of cytochrome P450 aromatic O-demethylases in the biological conversion of lignin-derived aromatic compounds.
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Venkatesagowda B. Enzymatic demethylation of lignin for potential biobased polymer applications. FUNGAL BIOL REV 2019. [DOI: 10.1016/j.fbr.2019.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Lubbers RJM, Dilokpimol A, Visser J, Mäkelä MR, Hildén KS, de Vries RP. A comparison between the homocyclic aromatic metabolic pathways from plant-derived compounds by bacteria and fungi. Biotechnol Adv 2019; 37:107396. [PMID: 31075306 DOI: 10.1016/j.biotechadv.2019.05.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 04/18/2019] [Accepted: 05/03/2019] [Indexed: 12/13/2022]
Abstract
Aromatic compounds derived from lignin are of great interest for renewable biotechnical applications. They can serve in many industries e.g. as biochemical building blocks for bioplastics or biofuels, or as antioxidants, flavor agents or food preservatives. In nature, lignin is degraded by microorganisms, which results in the release of homocyclic aromatic compounds. Homocyclic aromatic compounds can also be linked to polysaccharides, tannins and even found freely in plant biomass. As these compounds are often toxic to microbes already at low concentrations, they need to be degraded or converted to less toxic forms. Prior to ring cleavage, the plant- and lignin-derived aromatic compounds are converted to seven central ring-fission intermediates, i.e. catechol, protocatechuic acid, hydroxyquinol, hydroquinone, gentisic acid, gallic acid and pyrogallol through complex aromatic metabolic pathways and used as energy source in the tricarboxylic acid cycle. Over the decades, bacterial aromatic metabolism has been described in great detail. However, the studies on fungal aromatic pathways are scattered over different pathways and species, complicating a comprehensive view of fungal aromatic metabolism. In this review, we depicted the similarities and differences of the reported aromatic metabolic pathways in fungi and bacteria. Although both microorganisms share the main conversion routes, many alternative pathways are observed in fungi. Understanding the microbial aromatic metabolic pathways could lead to metabolic engineering for strain improvement and promote valorization of lignin and related aromatic compounds.
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Affiliation(s)
- Ronnie J M Lubbers
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
| | - Adiphol Dilokpimol
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
| | - Jaap Visser
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
| | - Miia R Mäkelä
- Department of Microbiology, University of Helsinki, Viikinkaari 9, Helsinki, Finland.
| | - Kristiina S Hildén
- Department of Microbiology, University of Helsinki, Viikinkaari 9, Helsinki, Finland.
| | - Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands; Department of Microbiology, University of Helsinki, Viikinkaari 9, Helsinki, Finland.
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Abstract
Production of fuels and chemicals from renewable lignocellulosic feedstocks is a promising alternative to petroleum-derived compounds. Due to the complexity of lignocellulosic feedstocks, microbial conversion of all potential substrates will require substantial metabolic engineering. Non-model microbes offer desirable physiological traits, but also increase the difficulty of heterologous pathway engineering and optimization. The development of modular design principles that allow metabolic pathways to be used in a variety of novel microbes with minimal strain-specific optimization will enable the rapid construction of microbes for commercial production of biofuels and bioproducts. In this review, we discuss variability of lignocellulosic feedstocks, pathways for catabolism of lignocellulose-derived compounds, challenges to heterologous engineering of catabolic pathways, and opportunities to apply modular pathway design. Implementation of these approaches will simplify the process of modifying non-model microbes to convert diverse lignocellulosic feedstocks.
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Lanfranchi E, Trajković M, Barta K, de Vries JG, Janssen DB. Exploring the Selective Demethylation of Aryl Methyl Ethers with a
Pseudomonas
Rieske Monooxygenase. Chembiochem 2018; 20:118-125. [DOI: 10.1002/cbic.201800594] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Elisa Lanfranchi
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of Groningen Nijenborgh 4 9726 AG Groningen The Netherlands
- Present address: School of Food and Nutritional Science SciencesUniversity College Cork College Road Cork T12 YN60 Republic of Ireland
| | - Miloš Trajković
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of Groningen Nijenborgh 4 9726 AG Groningen The Netherlands
| | - Katalin Barta
- Synthetic Organic ChemistryStratingh Institute for ChemistryUniversity of Groningen Nijenborgh 4 9726 AG Groningen The Netherlands
| | - Johannes G. de Vries
- Synthetic Organic ChemistryStratingh Institute for ChemistryUniversity of Groningen Nijenborgh 4 9726 AG Groningen The Netherlands
- Leibniz-Institut für Katalyse e.V. Albert-Einstein-Strasse 29a 18059 Rostock Germany
| | - Dick B. Janssen
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of Groningen Nijenborgh 4 9726 AG Groningen The Netherlands
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Mallinson SJB, Machovina MM, Silveira RL, Garcia-Borràs M, Gallup N, Johnson CW, Allen MD, Skaf MS, Crowley MF, Neidle EL, Houk KN, Beckham GT, DuBois JL, McGeehan JE. A promiscuous cytochrome P450 aromatic O-demethylase for lignin bioconversion. Nat Commun 2018; 9:2487. [PMID: 29950589 PMCID: PMC6021390 DOI: 10.1038/s41467-018-04878-2] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/26/2018] [Indexed: 11/18/2022] Open
Abstract
Microbial aromatic catabolism offers a promising approach to convert lignin, a vast source of renewable carbon, into useful products. Aryl-O-demethylation is an essential biochemical reaction to ultimately catabolize coniferyl and sinapyl lignin-derived aromatic compounds, and is often a key bottleneck for both native and engineered bioconversion pathways. Here, we report the comprehensive characterization of a promiscuous P450 aryl-O-demethylase, consisting of a cytochrome P450 protein from the family CYP255A (GcoA) and a three-domain reductase (GcoB) that together represent a new two-component P450 class. Though originally described as converting guaiacol to catechol, we show that this system efficiently demethylates both guaiacol and an unexpectedly wide variety of lignin-relevant monomers. Structural, biochemical, and computational studies of this novel two-component system elucidate the mechanism of its broad substrate specificity, presenting it as a new tool for a critical step in biological lignin conversion.
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Affiliation(s)
- Sam J B Mallinson
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Melodie M Machovina
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Rodrigo L Silveira
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Institute of Chemistry, University of Campinas, Campinas, Sao Paulo, 13083-970, Brazil
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Nathan Gallup
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Christopher W Johnson
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Mark D Allen
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Munir S Skaf
- Institute of Chemistry, University of Campinas, Campinas, Sao Paulo, 13083-970, Brazil
| | - Michael F Crowley
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Ellen L Neidle
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| | - Gregg T Beckham
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
| | - Jennifer L DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
| | - John E McGeehan
- Molecular Biophysics, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK.
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Kamimura N, Takahashi K, Mori K, Araki T, Fujita M, Higuchi Y, Masai E. Bacterial catabolism of lignin-derived aromatics: New findings in a recent decade: Update on bacterial lignin catabolism. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:679-705. [PMID: 29052962 DOI: 10.1111/1758-2229.12597] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/26/2017] [Accepted: 10/03/2017] [Indexed: 05/21/2023]
Abstract
Lignin is the most abundant phenolic polymer; thus, its decomposition by microorganisms is fundamental to carbon cycling on earth. Lignin breakdown is initiated by depolymerization catalysed by extracellular oxidoreductases secreted by white-rot basidiomycetous fungi. On the other hand, bacteria play a predominant role in the mineralization of lignin-derived heterogeneous low-molecular-weight aromatic compounds. The outline of bacterial catabolic pathways for lignin-derived bi- and monoaryls are typically composed of the following sequential steps: (i) funnelling of a wide variety of lignin-derived aromatics into vanillate and syringate, (ii) O demethylation of vanillate and syringate to form catecholic derivatives and (iii) aromatic ring-cleavage of the catecholic derivatives to produce tricarboxylic acid cycle intermediates. Knowledge regarding bacterial catabolic systems for lignin-derived aromatic compounds is not only important for understanding the terrestrial carbon cycle but also valuable for promoting the shift to a low-carbon economy via biological lignin valorisation. This review summarizes recent progress in bacterial catabolic systems for lignin-derived aromatic compounds, including newly identified catabolic pathways and genes for decomposition of lignin-derived biaryls, transcriptional regulation and substrate uptake systems. Recent omics approaches on catabolism of lignin-derived aromatic compounds are also described.
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Affiliation(s)
- Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Kenji Takahashi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Kosuke Mori
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Takuma Araki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masaya Fujita
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Yudai Higuchi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
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