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Xu L, Wang G, Zhang S, Li T, Xu X, Gong G, Zhou W, Pu Y, Jia Y, Li Y, Long L. Inhibition of high sulfur on functional microorganisms and genes in slightly contaminated soil by cadmium and chromium. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123421. [PMID: 38253166 DOI: 10.1016/j.envpol.2024.123421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/21/2023] [Accepted: 01/19/2024] [Indexed: 01/24/2024]
Abstract
It is generally accepted that sulfur can passivate the bioavailability of heavy metals in soil, but it is not clear whether high sulfur in cadmium (Cd) and chromium (Cr) contaminated soil has negative effect on soil microbial community and ecological function. In this study, total sulfur (TS) inhibited the Chao 1, Shannon, Phylogenetic diversity (Pd) of bacterial and Pd of fungi in slightly contaminated soil by Cd and Cr around pyrite. TS, total potassium, pH, total chromium, total cadmium, total nitrogen, soil organic matter were the predominant factors for soil microbial community; the contribution of TS in shaping bacterial and fungal communities ranked at first and fifth, respectively. Compared with the low sulfur group, the abundance of sulfur sensitive microorganisms Gemmatimonas, Pseudolabrys, MND1, and Schizothecium were decreased by 68.79-97.22% (p < 0.01) at high sulfur one; the carbon fixation, nitrogen cycling, phosphorus cycling and resistance genes abundance were significantly lower (p < 0.01) at the latter. Such variations were strongly and closely correlated to the suppression of energy metabolism (M00009, M00011, M00086) and carbon fixation (M00173, M00376) functional module genes abundance in the high sulfur group. Collectively, high sulfur significantly suppressed the abundances of functional microorganisms and functional genes in slightly contaminated soil with Cd and Cr, possibly through inhibition of energy metabolism and carbon fixation of functional microorganisms. This study provided new insights into the environmental behavior of sulfur in slightly contaminated soil with Cd and Cr.
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Affiliation(s)
- Longfei Xu
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, China.
| | - Guiyin Wang
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang, 611130, China
| | - Shirong Zhang
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang, 611130, China.
| | - Ting Li
- College of Resources, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Xiaoxun Xu
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang, 611130, China
| | - Guoshu Gong
- College of Agronomy, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Wei Zhou
- College of Resources, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Yulin Pu
- College of Resources, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Yongxia Jia
- College of Resources, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Yun Li
- College of Resources, Sichuan Agricultural University, Wenjiang, 611130, China
| | - Lulu Long
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang, 611130, China
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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.
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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.
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Acosta-Salazar E, Fonseca-Aguiñaga R, Warren-Vega WM, Zárate-Guzmán AI, Zárate-Navarro MA, Romero-Cano LA, Campos-Rodríguez A. Effect of Age of Agave tequilana Weber Blue Variety on Quality and Authenticity Parameters for the Tequila 100% Agave Silver Class: Evaluation at the Industrial Scale Level. Foods 2021; 10:foods10123103. [PMID: 34945653 PMCID: PMC8701365 DOI: 10.3390/foods10123103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/20/2021] [Accepted: 12/07/2021] [Indexed: 11/23/2022] Open
Abstract
Due to the oversupply and scarcity cycles of the Agave tequilana Weber blue variety, the effect of agave age (harvested in 4, 5, and 6 years) as raw material for the tequila 100% agave silver class was studied for each stage in a full-scale (industrial) process. Harvested plants showed differences in their morphological characteristics that affected the amount of juice; this had an impact in the fermentation stage since must composition was modified in the nitrogen content and juice/exudate ratio. This was noticed due to an increase in the production of higher alcohols attributed to the odd-chain fatty of the exudate, which affects n-propanol production. The characterization of the final product showed the feasibility to use agaves (less than 7 years) to produce the Tequila 100% agave silver class and to comply with the quality criteria. Furthermore, the final product was analyzed with the gas chromatography-isotope ratio mass-spectrometry technique to determine its authenticity. The δ13CVPDB isotopic parameter (−13.40‰ in average) values show the type of plant used as a raw material for ethanol production, while the δ18OVSMOW (20.52‰ in average) isotopic parameter can be helpful in corroborating and ensuring the traceability of the product and the geographical location of the beverage production.
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Affiliation(s)
- Efraín Acosta-Salazar
- Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (E.A.-S.); (M.A.Z.-N.)
| | - Rocío Fonseca-Aguiñaga
- Grupo de Investigación en Materiales y Fenómenos de Superficie, Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (R.F.-A.); (W.M.W.-V.); (A.I.Z.-G.)
- Laboratorio de Isotopía, Consejo Regulador del Tequila A. C., Av. Patria 723, Zapopan 45030, Mexico
| | - Walter M. Warren-Vega
- Grupo de Investigación en Materiales y Fenómenos de Superficie, Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (R.F.-A.); (W.M.W.-V.); (A.I.Z.-G.)
| | - Ana I. Zárate-Guzmán
- Grupo de Investigación en Materiales y Fenómenos de Superficie, Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (R.F.-A.); (W.M.W.-V.); (A.I.Z.-G.)
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78060, Mexico
| | - Marco A. Zárate-Navarro
- Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (E.A.-S.); (M.A.Z.-N.)
| | - Luis A. Romero-Cano
- Grupo de Investigación en Materiales y Fenómenos de Superficie, Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (R.F.-A.); (W.M.W.-V.); (A.I.Z.-G.)
- Correspondence: (L.A.R.-C.); (A.C.-R.)
| | - Armando Campos-Rodríguez
- Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, Zapopan 45129, Mexico; (E.A.-S.); (M.A.Z.-N.)
- Correspondence: (L.A.R.-C.); (A.C.-R.)
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Mutagenesis separates ATPase and thioesterase activities of the peroxisomal ABC transporter, Comatose. Sci Rep 2019; 9:10502. [PMID: 31324846 PMCID: PMC6642094 DOI: 10.1038/s41598-019-46685-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/27/2019] [Indexed: 01/11/2023] Open
Abstract
The peroxisomal ABC transporter, Comatose (CTS), a full length transporter from Arabidopsis has intrinsic acyl-CoA thioesterase (ACOT) activity, important for physiological function. We used molecular modelling, mutagenesis and biochemical analysis to identify amino acid residues important for ACOT activity. D863, Q864 and T867 lie within transmembrane helix 9. These residues are orientated such that they might plausibly contribute to a catalytic triad similar to type II Hotdog fold thioesterases. When expressed in Saccharomyces cerevisiae, mutation of these residues to alanine resulted in defective of β-oxidation. All CTS mutants were expressed and targeted to peroxisomes and retained substrate-stimulated ATPase activity. When expressed in insect cell membranes, Q864A and S810N had similar ATPase activity to wild type but greatly reduced ACOT activity, whereas the Walker A mutant K487A had greatly reduced ATPase and no ATP-dependent ACOT activity. In wild type CTS, ATPase but not ACOT was stimulated by non-cleavable C14 ether-CoA. ACOT activity was stimulated by ATP but not by non-hydrolysable AMPPNP. Thus, ACOT activity depends on functional ATPase activity but not vice versa, and these two activities can be separated by mutagenesis. Whether D863, Q864 and T867 have a catalytic role or play a more indirect role in NBD-TMD communication is discussed.
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Biernacki M, Riechen J, Hähnel U, Roick T, Baronian K, Bode R, Kunze G. Production of (R)-3-hydroxybutyric acid by Arxula adeninivorans. AMB Express 2017; 7:4. [PMID: 28050847 PMCID: PMC5209319 DOI: 10.1186/s13568-016-0303-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/11/2016] [Indexed: 12/28/2022] Open
Abstract
(R)-3-hydroxybutyric acid can be used in industrial and health applications. The synthesis pathway comprises two enzymes, β-ketothiolase and acetoacetyl-CoA reductase which convert cytoplasmic acetyl-CoA to (R)-3-hydroxybutyric acid [(R)-3-HB] which is released into the culture medium. In the present study we used the non-conventional yeast, Arxula adeninivorans, for the synthesis enantiopure (R)-3-HB. To establish optimal production, we investigated three different endogenous yeast thiolases (Akat1p, Akat2p, Akat4p) and three bacterial thiolases (atoBp, thlp, phaAp) in combination with an enantiospecific reductase (phaBp) from Cupriavidus necator H16 and endogenous yeast reductases (Atpk2p, Afox2p). We found that Arxula is able to release (R)-3-HB used an existing secretion system negating the need to engineer membrane transport. Overexpression of thl and phaB genes in organisms cultured in a shaking flask resulted in 4.84 g L−1 (R)-3-HB, at a rate of 0.023 g L−1 h−1 over 214 h. Fed-batch culturing with glucose as a carbon source did not improve the yield, but a similar level was reached with a shorter incubation period [3.78 g L−1 of (R)-3-HB at 89 h] and the rate of production was doubled to 0.043 g L−1 h−1 which is higher than any levels in yeast reported to date. The secreted (R)-3-HB was 99.9% pure. This is the first evidence of enantiopure (R)-3-HB synthesis using yeast as a production host and glucose as a carbon source.
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Han L, Peng Y, Zhang Y, Chen W, Lin Y, Wang Q. Designing and Creating a Synthetic Omega Oxidation Pathway in Saccharomyces cerevisiae Enables Production of Medium-Chain α, ω-Dicarboxylic Acids. Front Microbiol 2017; 8:2184. [PMID: 29163455 PMCID: PMC5673993 DOI: 10.3389/fmicb.2017.02184] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/24/2017] [Indexed: 11/24/2022] Open
Abstract
Medium-chain (C8–C14) α, ω-dicarboxylic acids (α, ω-DCAs), which have numerous applications as raw materials for producing various commodities and polymers in chemical industry, are mainly produced from chemical or microbial conversion of petroleum-derived alkanes or plant-derived fatty acids at present. Recently, significant attention has been gained to microbial production of medium-chain α, ω-DCAs from simple renewable sugars. Here, we designed and created a synthetic omega oxidation pathway in Saccharomyces cerevisiae to produce C10 and C12 α, ω-DCAs from renewable sugars and fatty acids by introducing a heterogeneous cytochrome P450 CYP94C1 and cytochrome reductase ATR1. Furthermore, the deletion of fatty acyl-CoA synthetase genes FAA1 and FAA4 increased the production of medium-chain α, ω-DCAs from 4.690 ± 0.088 mg/L to 12.177 ± 0.420 mg/L and enabled the production of C14 and C16 α, ω-DCAs at low percentage. But blocking β-oxidation pathway by deleting fatty-acyl coenzyme A oxidase gene POX1 and overexpressing different thioesterase genes had no significant impact on the production and the composition of α, ω-dicarboxylic acids. Overall, our study indicated the potential of microbial production of medium-chain α, ω-DCAs from renewable feedstocks using engineered yeast.
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Affiliation(s)
- Li Han
- School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou, China.,CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Yanfeng Peng
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Yuangyuan Zhang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Wujiu Chen
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Yuping Lin
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Qinhong Wang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
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Fernandez-Moya R, Da Silva NA. Engineering Saccharomyces cerevisiae for high-level synthesis of fatty acids and derived products. FEMS Yeast Res 2017; 17:4111148. [DOI: 10.1093/femsyr/fox071] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 09/10/2017] [Indexed: 01/16/2023] Open
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Cámara E, Landes N, Albiol J, Gasser B, Mattanovich D, Ferrer P. Increased dosage of AOX1 promoter-regulated expression cassettes leads to transcription attenuation of the methanol metabolism in Pichia pastoris. Sci Rep 2017; 7:44302. [PMID: 28295011 PMCID: PMC5353721 DOI: 10.1038/srep44302] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 02/07/2017] [Indexed: 12/11/2022] Open
Abstract
The methanol-regulated alcohol oxidase promoter (PAOX1) of Pichia pastoris is one of the strongest promoters for heterologous gene expression in this methylotrophic yeast. Although increasing gene dosage is one of the most common strategies to increase recombinant protein productivities, the increase of gene dosage of Rhizopus oryzae lipase (ROL) in P. pastoris has been previously shown to reduce cell growth, lipase production and substrate consumption in high-copy strains. To better assess that physiological response, transcriptomics analysis was performed of a subset of strains with 1 to 15 ROL copies. The macroscopic physiological parameters confirm that growth yield and carbon uptake rate are gene dosage dependent, and were supported by the transcriptomic data, showing the impact of increased dosage of AOX1 promoter-regulated expression cassettes on P. pastoris physiology under steady methanolic growth conditions. Remarkably, increased number of cassettes led to transcription attenuation of the methanol metabolism and peroxisome biogenesis in P. pastoris, concomitant with reduced secretion levels of the heterologous product. Moreover, our data also point to a block in ROL mRNA translation in the higher ROL-copies constructs, while the low productivities of multi-copy strains under steady growth conditions do not appear to be directly related to UPR and ERAD induction.
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Affiliation(s)
- Elena Cámara
- Department of Chemical, Biological, and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès) 08193, Catalonia, Spain
| | - Nils Landes
- Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 18, 1190 Vienna, Austria.,Austrian Centre of Industrial Biotechnology, A-1190 Vienna, Austria
| | - Joan Albiol
- Department of Chemical, Biological, and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès) 08193, Catalonia, Spain
| | - Brigitte Gasser
- Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 18, 1190 Vienna, Austria.,Austrian Centre of Industrial Biotechnology, A-1190 Vienna, Austria
| | - Diethard Mattanovich
- Department of Biotechnology, BOKU - University of Natural Resources and Life Sciences Vienna, Muthgasse 18, 1190 Vienna, Austria.,Austrian Centre of Industrial Biotechnology, A-1190 Vienna, Austria
| | - Pau Ferrer
- Department of Chemical, Biological, and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès) 08193, Catalonia, Spain
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Lozano-Martínez P, Buey RM, Ledesma-Amaro R, Jiménez A, Revuelta JL. Engineering Ashbya gossypii strains for de novo lipid production using industrial by-products. Microb Biotechnol 2016; 10:425-433. [PMID: 28008713 PMCID: PMC5328814 DOI: 10.1111/1751-7915.12487] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 11/27/2022] Open
Abstract
Ashbya gossypii is a filamentous fungus that naturally overproduces riboflavin, and it is currently exploited for the industrial production of this vitamin. The utilization of A. gossypii for biotechnological applications presents important advantages such as the utilization of low-cost culture media, inexpensive downstream processing and a wide range of molecular tools for genetic manipulation, thus making A. gossypii a valuable biotechnological chassis for metabolic engineering. A. gossypii has been shown to accumulate high levels of lipids in oil-based culture media; however, the lipid biosynthesis capacity is rather limited when grown in sugar-based culture media. In this study, by altering the fatty acyl-CoA pool and manipulating the regulation of the main ∆9 desaturase gene, we have obtained A. gossypii strains with significantly increased (up to fourfold) de novo lipid biosynthesis using glucose as the only carbon source in the fermentation broth. Moreover, these strains were efficient biocatalysts for the conversion of carbohydrates from sugarcane molasses to biolipids, able to accumulate lipids up to 25% of its cell dry weight. Our results represent a proof of principle showing the promising potential of A. gossypii as a competitive microorganism for industrial biolipid production using cost-effective feed stocks.
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Affiliation(s)
- Patricia Lozano-Martínez
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - Rubén M Buey
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - Rodrigo Ledesma-Amaro
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - Alberto Jiménez
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - José Luis Revuelta
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
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Production of (S)-3-hydroxybutyrate by metabolically engineered Saccharomyces cerevisiae. J Biotechnol 2015; 209:23-30. [DOI: 10.1016/j.jbiotec.2015.05.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/27/2015] [Accepted: 05/25/2015] [Indexed: 11/22/2022]
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Tilbrook K, Poirier Y, Gebbie L, Schenk PM, McQualter RB, Brumbley SM. Reduced peroxisomal citrate synthase activity increases substrate availability for polyhydroxyalkanoate biosynthesis in plant peroxisomes. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:1044-1052. [PMID: 24944109 DOI: 10.1111/pbi.12211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/25/2014] [Accepted: 05/01/2014] [Indexed: 06/03/2023]
Abstract
Polyhydroxyalkanoates (PHAs) are bacterial carbon storage polymers used as renewable, biodegradable plastics. PHA production in plants may be a way to reduce industrial PHA production costs. We recently demonstrated a promising level of peroxisomal PHA production in the high biomass crop species sugarcane. However, further production strategies are needed to boost PHA accumulation closer to commercial targets. Through exogenous fatty acid feeding of Arabidopsis thaliana plants that contain peroxisome-targeted PhaA, PhaB and PhaC enzymes from Cupriavidus necator, we show here that the availability of substrates derived from the β-oxidation cycle limits peroxisomal polyhydroxybutyrate (PHB) biosynthesis. Knockdown of peroxisomal citrate synthase activity using artificial microRNA increased PHB production levels approximately threefold. This work demonstrates that reduction of peroxisomal citrate synthase activity may be a valid metabolic engineering strategy for increasing PHA production in other plant species.
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Affiliation(s)
- Kimberley Tilbrook
- School of Biological Science, The University of Queensland, Brisbane, Qld, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia; The Cooperative Research Centre for Sugar Industry Innovation through Biotechnology, The University of Queensland, Brisbane, Qld, Australia
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Enhancement of free fatty acid production in Saccharomyces cerevisiae by control of fatty acyl-CoA metabolism. Appl Microbiol Biotechnol 2014; 98:6739-50. [PMID: 24769906 DOI: 10.1007/s00253-014-5758-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 01/05/2023]
Abstract
Production of biofuels derived from microbial fatty acids has attracted great attention in recent years owing to their potential to replace petroleum-derived fuels. To be cost competitive with current petroleum fuel, flux toward the direct precursor fatty acids needs to be enhanced to approach high yields. Herein, fatty acyl-CoA metabolism in Saccharomyces cerevisiae was engineered to accumulate more free fatty acids (FFA). For this purpose, firstly, haploid S. cerevisiae double deletion strain △faa1△faa4 was constructed, in which the genes FAA1 and FAA4 encoding two acyl-CoA synthetases were deleted. Then the truncated version of acyl-CoA thioesterase ACOT5 (Acot5s) encoding Mus musculus peroxisomal acyl-CoA thioesterase 5 was expressed in the cytoplasm of the strain △faa1△faa4. The resulting strain △faa1△faa4 [Acot5s] accumulated more extracellular FFA with higher unsaturated fatty acid (UFA) ratio as compared to the wild-type strain and double deletion strain △faa1△faa4. The extracellular total fatty acids (TFA) in the strain △faa1△faa4 [Acot5s] increased to 6.43-fold as compared to the wild-type strain during the stationary phase. UFA accounted for 42 % of TFA in the strain △faa1△faa4 [Acot5s], while no UFA was detected in the wild-type strain. In addition, the expression of Acot5s in △faa1△faa4 restored the growth, which indicates that FFA may not be the reason for growth inhibition in the strain △faa1△faa4. RT-PCR results demonstrated that the de-repression of fatty acid synthesis genes led to the increase of extracellular fatty acids. The study presented here showed that through control of the acyl-CoA metabolism by deleting acyl-CoA synthetase and expressing thioesterase, more FFA could be produced in S. cerevisiae, demonstrating great potential for exploitation in the platform of microbial fatty acid-derived biofuels.
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Hunt MC, Tillander V, Alexson SEH. Regulation of peroxisomal lipid metabolism: the role of acyl-CoA and coenzyme A metabolizing enzymes. Biochimie 2014; 98:45-55. [PMID: 24389458 DOI: 10.1016/j.biochi.2013.12.018] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/19/2013] [Indexed: 12/11/2022]
Abstract
Peroxisomes are nearly ubiquitous organelles involved in a number of metabolic pathways that vary between organisms and tissues. A common metabolic function in mammals is the partial degradation of various (di)carboxylic acids via α- and β-oxidation. While only a small number of enzymes catalyze the reactions of β-oxidation, numerous auxiliary enzymes have been identified to be involved in uptake of fatty acids and cofactors required for β-oxidation, regulation of β-oxidation and transport of metabolites across the membrane. These proteins include membrane transporters/channels, acyl-CoA thioesterases, acyl-CoA:amino acid N-acyltransferases, carnitine acyltransferases and nudix hydrolases. Here we review the current view of the role of these auxiliary enzymes in peroxisomal lipid metabolism and propose that they function in concert to provide a means to regulate fatty acid metabolism and transport of products across the peroxisomal membrane.
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Affiliation(s)
- Mary C Hunt
- Dublin Institute of Technology, College of Sciences & Health, School of Biological Sciences, Kevin Street, Dublin 8, Ireland.
| | - Veronika Tillander
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska University Hospital, SE 141 86, Stockholm, Sweden
| | - Stefan E H Alexson
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska University Hospital, SE 141 86, Stockholm, Sweden
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Functional screening and in vitro analysis reveal thioesterases with enhanced substrate specificity profiles that improve short-chain fatty acid production in Escherichia coli. Appl Environ Microbiol 2013; 80:1042-50. [PMID: 24271180 DOI: 10.1128/aem.03303-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Short-chain fatty acid (SCFA) biosynthesis is pertinent to production of biofuels, industrial compounds, and pharmaceuticals from renewable resources. To expand on Escherichia coli SCFA products, we previously implemented a coenzyme A (CoA)-dependent pathway that condenses acetyl-CoA to a diverse group of short-chain fatty acyl-CoAs. To increase product titers and reduce premature pathway termination products, we conducted in vivo and in vitro analyses to understand and improve the specificity of the acyl-CoA thioesterase enzyme, which releases fatty acids from CoA. A total of 62 putative bacterial thioesterases, including 23 from the cow rumen microbiome, were inserted into a pathway that condenses acetyl-CoA to an acyl-CoA molecule derived from exogenously provided propionic or isobutyric acid. Functional screening revealed thioesterases that increase production of saturated (valerate), unsaturated (trans-2-pentenoate), and branched (4-methylvalerate) SCFAs compared to overexpression of E. coli thioesterase tesB or native expression of endogenous thioesterases. To determine if altered thioesterase acyl-CoA substrate specificity caused the increase in product titers, six of the most promising enzymes were analyzed in vitro. Biochemical assays revealed that the most productive thioesterases rely on promiscuous activity but have greater specificity for product-associated acyl-CoAs than for precursor acyl-CoAs. In this study, we introduce novel thioesterases with improved specificity for saturated, branched, and unsaturated short-chain acyl-CoAs, thereby expanding the diversity of potential fatty acid products while increasing titers of current products. The growing uncertainty associated with protein database annotations denotes this study as a model for isolating functional biochemical pathway enzymes in situations where experimental evidence of enzyme function is absent.
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Chung AL, Zeng GD, Jin HL, Wu Q, Chen JC, Chen GQ. Production of medium-chain-length 3-hydroxyalkanoic acids by β-oxidation and phaC operon deleted Pseudomonas entomophila harboring thioesterase gene. Metab Eng 2013; 17:23-9. [DOI: 10.1016/j.ymben.2013.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 02/13/2013] [Accepted: 02/25/2013] [Indexed: 10/27/2022]
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16
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Caloric restriction restores the chronological life span of the Goa1 null mutant of Candida albicans in spite of high cell levels of ROS. Fungal Genet Biol 2012; 49:1023-32. [PMID: 23063955 DOI: 10.1016/j.fgb.2012.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/11/2012] [Accepted: 09/13/2012] [Indexed: 02/05/2023]
Abstract
The Candida albicans Goa1p is required for mitochondrial functions. In a strain lacking GOA1 (GOA31), respiration, mitochondrial membrane potential, complex I (CI) activity of the electron transport chain, and ATP synthesis are significantly decreased. A shortened chronological life span (CLS) of GOA31 occurs in 2% glucose that is associated with an increase in cell reactive oxidant species (ROS) and apoptosis. We now show that caloric restriction (CR) in media containing 0.5% glucose instead of 2% glucose-SC extends the CLS to the level of parental and gene-reconstituted strains. Paradoxically, ROS levels in GOA31 far exceed those of control strains in 0.5% glucose and, as a consequence, increased lipid peroxidation occurs even though CLS is restored. Microarray analysis was used to characterize transcriptional changes during CR in GOA31. We found that CR shifts cells of all strains to a non-glucose carbon metabolism (β-oxidation). Our model of ROS formation in GOA31 follows the paradigm that the generation of oxygen radicals from β-oxidation of cell lipids via FADH(2) (CII) and NADH (CI) creates an unfavorable cellular FADH(2)/NADH ratio that causes a transient overload in CII activity resulting in excess free cell radicals. In GOA31 the CI and peroxisomal dysfunctions increase the levels of ROS compared to control strains. Recovery from high levels of ROS may be associated with an increase in iron and sugar transporters, as well as an anti-stress response that includes the SOD1 and GPX1. Thus, CR creates a favorable growth environment, but cells of GOA31 must overcome a high but transient ROS production.
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17
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Hunt MC, Siponen MI, Alexson SEH. The emerging role of acyl-CoA thioesterases and acyltransferases in regulating peroxisomal lipid metabolism. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1397-410. [PMID: 22465940 DOI: 10.1016/j.bbadis.2012.03.009] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/03/2012] [Accepted: 03/16/2012] [Indexed: 11/28/2022]
Abstract
The importance of peroxisomes in lipid metabolism is now well established and peroxisomes contain approximately 60 enzymes involved in these lipid metabolic pathways. Several acyl-CoA thioesterase enzymes (ACOTs) have been identified in peroxisomes that catalyze the hydrolysis of acyl-CoAs (short-, medium-, long- and very long-chain), bile acid-CoAs, and methyl branched-CoAs, to the free fatty acid and coenzyme A. A number of acyltransferase enzymes, which are structurally and functionally related to ACOTs, have also been identified in peroxisomes, which conjugate (or amidate) bile acid-CoAs and acyl-CoAs to amino acids, resulting in the production of amidated bile acids and fatty acids. The function of ACOTs is to act as auxiliary enzymes in the α- and β-oxidation of various lipids in peroxisomes. Human peroxisomes contain at least two ACOTs (ACOT4 and ACOT8) whereas mouse peroxisomes contain six ACOTs (ACOT3, 4, 5, 6, 8 and 12). Similarly, human peroxisomes contain one bile acid-CoA:amino acid N-acyltransferase (BAAT), whereas mouse peroxisomes contain three acyltransferases (BAAT and acyl-CoA:amino acid N-acyltransferases 1 and 2: ACNAT1 and ACNAT2). This review will focus on the human and mouse peroxisomal ACOT and acyltransferase enzymes identified to date and discuss their cellular localizations, emerging structural information and functions as auxiliary enzymes in peroxisomal metabolic pathways.
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Affiliation(s)
- Mary C Hunt
- Dublin Institute of Technology, Dublin 8, Ireland.
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18
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Modelling the peroxisomal carbon leak during lipid mobilization in Arabidopsis. Biochem Soc Trans 2011; 38:1230-3. [PMID: 20863290 DOI: 10.1042/bst0381230] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutation of the ACN1 (acetate non-utilizing 1) locus of Arabidopsis results in altered acetate assimilation into gluconeogenic sugars and anapleurotic amino acids and leads to an overall depression in primary metabolite levels by approx. 50% during seedling development. Levels of acetyl-CoA were higher in acn1 compared with wild-type, which is counterintuitive to the activity of ACN1 as a peroxisomal acetyl-CoA synthetase. We hypothesize that ACN1 recycles free acetate to acetyl-CoA within peroxisomes in order that carbon remains fed into the glyoxylate cycle. When ACN1 is not present, carbon in the form of acetate can leak out of peroxisomes and is reactivated to acetyl-CoA within the cytosol. Kinetic models incorporating estimates of carbon input and pathway dynamics from a variety of literature sources have proven useful in explaining how ACN1 may prevent the carbon leak and even contribute to the control of peroxisomal carbon metabolism.
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Genetic replacement of tesB with PTE1 affects chain-length proportions of 3-hydroxyalkanoic acids produced through β-oxidation of oleic acid in Escherichia coli. J Biosci Bioeng 2010; 110:392-6. [DOI: 10.1016/j.jbiosc.2010.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 05/04/2010] [Accepted: 05/12/2010] [Indexed: 11/17/2022]
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20
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Haddouche R, Delessert S, Sabirova J, Neuvéglise C, Poirier Y, Nicaud JM. Roles of multiple acyl-CoA oxidases in the routing of carbon flow towards β-oxidation and polyhydroxyalkanoate biosynthesis in Yarrowia lipolytica. FEMS Yeast Res 2010; 10:917-27. [PMID: 20726896 DOI: 10.1111/j.1567-1364.2010.00670.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The oleaginous yeast Yarrowia lipolytica possesses six acyl-CoA oxidase (Aox) isoenzymes encoded by genes POX1-POX6. The respective roles of these multiple Aox isoenzymes were studied in recombinant Y. lipolytica strains that express heterologous polyhydroxyalkanoate (PHA) synthase (phaC) of Pseudomonas aeruginosa in varying POX genetic backgrounds, thus allowing assessment of the impact of specific Aox enzymes on the routing of carbon flow to β-oxidation or to PHA biosynthesis. Analysis of PHA production yields during growth on fatty acids with different chain lengths has revealed that the POX genotype significantly affects the PHA levels, but not the monomer composition of PHA. Aox3p function was found to be responsible for 90% and 75% of the total PHA produced from either C9:0 or C13:0 fatty acid, respectively, whereas Aox5p encodes the main Aox involved in the biosynthesis of 70% of PHA from C9:0 fatty acid. Other Aoxs, such as Aox1p, Aox2p, Aox4p and Aox6p, were not found to play a significant role in PHA biosynthesis, independent of the chain length of the fatty acid used. Finally, three known models of β-oxidation are discussed and it is shown that a 'leaky-hose pipe model' of the cycle can be applied to Y. lipolytica.
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21
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Poirier Y, Brumbley SM. Metabolic Engineering of Plants for the Synthesis of Polyhydroxyalkanaotes. MICROBIOLOGY MONOGRAPHS 2010. [DOI: 10.1007/978-3-642-03287-5_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Ntamack AG, Karpichev IV, Gould SJ, Small GM, Schulz H. Oleate beta-oxidation in yeast involves thioesterase but not Yor180c protein that is not a dienoyl-CoA isomerase. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:371-8. [PMID: 19830908 DOI: 10.1016/j.bbalip.2009.01.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The beta-oxidation of oleic acid in Saccharomyces cerevisiae (S. cerevisiae) was studied by comparing the growth of wild-type cells on oleic acid or palmitic acid with the growth of mutants that either had a deletion in the YOR180c (DCI1) gene reported to encode delta3,5,delta2,4-dienoyl-CoA isomerase (dienoyl-CoA isomerase) or in the PTE1 gene encoding peroxisomal thioesterase 1. Growth of wild-type cells was indistinguishable from that of YOR180c mutant cells on either palmitic acid or oleic acid, whereas the PTE1 mutant grew slower and to a lower density on oleic acid but not on palmitic acid. The identification of 3,5-tetradecadienoic acid in the medium of wild-type cells but not in the medium of the PTE1 mutant proves the operation of the thioesterase-dependent pathway of oleate beta-oxidation in S. cerevisiae. Dienoyl-CoA isomerase activity was very low in wild-type cells, fourfold higher in the YOR180c mutant, and not associated with purified Yor180c protein. These observations support the conclusion that the YOR180c gene does not encode dienoyl-CoA isomerase.
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Affiliation(s)
- André G Ntamack
- Department of Chemistry, City College and Graduate School of the City University of New York, New York, NY 10031, USA
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23
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Linka N, Theodoulou FL, Haslam RP, Linka M, Napier JA, Neuhaus HE, Weber APM. Peroxisomal ATP import is essential for seedling development in Arabidopsis thaliana. THE PLANT CELL 2008; 20:3241-57. [PMID: 19073763 PMCID: PMC2630453 DOI: 10.1105/tpc.108.062042] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Several recent proteomic studies of plant peroxisomes indicate that the peroxisomal matrix harbors multiple ATP-dependent enzymes and chaperones. However, it is unknown whether plant peroxisomes are able to produce ATP by substrate-level phosphorylation or whether external ATP fuels the energy-dependent reactions within peroxisomes. The existence of transport proteins that supply plant peroxisomes with energy for fatty acid oxidation and other ATP-dependent processes has not previously been demonstrated. Here, we describe two Arabidopsis thaliana genes that encode peroxisomal adenine nucleotide carriers, PNC1 and PNC2. Both proteins, when fused to enhanced yellow fluorescent protein, are targeted to peroxisomes. Complementation of a yeast mutant deficient in peroxisomal ATP import and in vitro transport assays using recombinant transporter proteins revealed that PNC1 and PNC2 catalyze the counterexchange of ATP with ADP or AMP. Transgenic Arabidopsis lines repressing both PNC genes were generated using ethanol-inducible RNA interference. A detailed analysis of these plants showed that an impaired peroxisomal ATP import inhibits fatty acid breakdown during early seedling growth and other beta-oxidation reactions, such as auxin biosynthesis. We show conclusively that PNC1 and PNC2 are essential for supplying peroxisomes with ATP, indicating that no other ATP generating systems exist inside plant peroxisomes.
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Affiliation(s)
- Nicole Linka
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, D-40225 Düsseldorf, Germany.
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24
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Abstract
Storage oil mobilization starts with the onset of seed germination. Oil bodies packed with triacylglycerol (TAG) exist in close proximity with glyoxysomes, the single membrane-bound organelles that house most of the biochemical machinery required to convert fatty acids derived from TAG to 4-carbon compounds. The 4-carbon compounds in turn are converted to soluble sugars that are used to fuel seedling growth. Biochemical analysis over the last 50 years has identified the main pathways involved in this process, including beta-oxidation, the glyoxylate cycle, and gluconeogenesis. In the last few years molecular genetic dissection of the overall process in the model oilseed species Arabidopsis has provided new insight into its complexity, particularly with respect to the specific role played by individual enzymatic steps and the subcellular compartmentalization of the glyoxylate cycle. Both abscisic acid (ABA) and sugars inhibit storage oil mobilization and a substantial degree of the control appears to operate at the transcriptional level.
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Affiliation(s)
- Ian A Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5YW, United Kingdom.
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25
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Goepfert S, Poirier Y. Beta-oxidation in fatty acid degradation and beyond. CURRENT OPINION IN PLANT BIOLOGY 2007; 10:245-51. [PMID: 17434787 DOI: 10.1016/j.pbi.2007.04.007] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 04/03/2007] [Indexed: 05/14/2023]
Abstract
The degradation of fatty acids in plants occurs primarily in the peroxisomes through the beta-oxidation cycle. Enzymes that are involved in various aspects of beta-oxidation have been identified recently and shown to act biochemically on a diversity of fatty acids and derivatives. Analysis of several mutants has revealed essential roles for beta-oxidation in the breakdown of reserve triacylglycerols, seed development, seed germination and post-germinative growth before the establishment of photosynthesis. Beta-oxidation has also a considerable importance during the vegetative and reproductive growth phases, and plays a role in plant responses to stress, particularly in the synthesis of jasmonic acid.
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Affiliation(s)
- Simon Goepfert
- Department of Plant Molecular Biology, Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland
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26
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Current awareness on yeast. Yeast 2006. [DOI: 10.1002/yea.1321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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27
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Poirier Y, Antonenkov VD, Glumoff T, Hiltunen JK. Peroxisomal beta-oxidation--a metabolic pathway with multiple functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1413-26. [PMID: 17028011 DOI: 10.1016/j.bbamcr.2006.08.034] [Citation(s) in RCA: 333] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 08/21/2006] [Accepted: 08/23/2006] [Indexed: 12/15/2022]
Abstract
Fatty acid degradation in most organisms occurs primarily via the beta-oxidation cycle. In mammals, beta-oxidation occurs in both mitochondria and peroxisomes, whereas plants and most fungi harbor the beta-oxidation cycle only in the peroxisomes. Although several of the enzymes participating in this pathway in both organelles are similar, some distinct physiological roles have been uncovered. Recent advances in the structural elucidation of numerous mammalian and yeast enzymes involved in beta-oxidation have shed light on the basis of the substrate specificity for several of them. Of particular interest is the structural organization and function of the type 1 and 2 multifunctional enzyme (MFE-1 and MFE-2), two enzymes evolutionarily distant yet catalyzing the same overall enzymatic reactions but via opposite stereochemistry. New data on the physiological roles of the various enzymes participating in beta-oxidation have been gathered through the analysis of knockout mutants in plants, yeast and animals, as well as by the use of polyhydroxyalkanoate synthesis from beta-oxidation intermediates as a tool to study carbon flux through the pathway. In plants, both forward and reverse genetics performed on the model plant Arabidopsis thaliana have revealed novel roles for beta-oxidation in the germination process that is independent of the generation of carbohydrates for growth, as well as in embryo and flower development, and the generation of the phytohormone indole-3-acetic acid and the signal molecule jasmonic acid.
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Affiliation(s)
- Yves Poirier
- Department of Plant Molecular Biology, Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland
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