1
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Rojas SAT, Boles E, Oreb M. A yeast-based in vivo assay system for analyzing efflux of sugars mediated by glucose and xylose transporters. FEMS Yeast Res 2022; 21:6653521. [PMID: 35918180 DOI: 10.1093/femsyr/foac038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/14/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
Sugar transporter research focuses on the sugar uptake into cells. Under certain physiological conditions, however, the intracellular accumulation and secretion of carbohydrates (efflux) are relevant processes in many cell types. Currently, no cell-based system is available for specifically investigating glucose efflux. Therefore, we designed a system based on a hexose transporter-deficient Saccharomyces cerevisiae strain, in which the disaccharide maltose is provided as a donor of intracellular glucose. By deleting the hexokinase genes, we prevented the metabolization of glucose and thereby achieved the accumulation of growth-inhibitory glucose levels inside the cells. When a permease mediating glucose efflux is expressed in this system, the inhibitory effect is relieved proportionally to the capacity of the introduced transporter. The assay is thereby suitable for screening of transporters and quantitative analyses of their glucose efflux capacities. Moreover, by simultaneous provision of intracellular glucose and extracellular xylose, we investigated how each sugar influences the transport of the other one from the opposite side of the membrane. Thereby, we could show that the xylose transporter variant Gal2N376F is insensitive not only to extracellular but also to intracellular glucose. Considering the importance of sugar transporters in biotechnology, the assay could facilitate new developments in a variety of applications.
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Affiliation(s)
- Sebastian A Tamayo Rojas
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
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2
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Bruni F, Giancaspero TA, Oreb M, Tolomeo M, Leone P, Boles E, Roberti M, Caselle M, Barile M. Subcellular Localization of Fad1p in Saccharomyces cerevisiae: A Choice at Post-Transcriptional Level? Life (Basel) 2021; 11:life11090967. [PMID: 34575116 PMCID: PMC8470081 DOI: 10.3390/life11090967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/13/2021] [Indexed: 11/24/2022] Open
Abstract
FAD synthase is the last enzyme in the pathway that converts riboflavin into FAD. In Saccharomyces cerevisiae, the gene encoding for FAD synthase is FAD1, from which a sole protein product (Fad1p) is expected to be generated. In this work, we showed that a natural Fad1p exists in yeast mitochondria and that, in its recombinant form, the protein is able, per se, to both enter mitochondria and to be destined to cytosol. Thus, we propose that FAD1 generates two echoforms—that is, two identical proteins addressed to different subcellular compartments. To shed light on the mechanism underlying the subcellular destination of Fad1p, the 3′ region of FAD1 mRNA was analyzed by 3′RACE experiments, which revealed the existence of (at least) two FAD1 transcripts with different 3′UTRs, the short one being 128 bp and the long one being 759 bp. Bioinformatic analysis on these 3′UTRs allowed us to predict the existence of a cis-acting mitochondrial localization motif, present in both the transcripts and, presumably, involved in protein targeting based on the 3′UTR context. Here, we propose that the long FAD1 transcript might be responsible for the generation of mitochondrial Fad1p echoform.
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Affiliation(s)
- Francesco Bruni
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
| | - Teresa Anna Giancaspero
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany; (M.O.); (E.B.)
| | - Maria Tolomeo
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
| | - Piero Leone
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany; (M.O.); (E.B.)
| | - Marina Roberti
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
| | - Michele Caselle
- Physics Department, University of Turin and INFN, Via P. Giuria 1, 10125 Turin, Italy;
| | - Maria Barile
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (F.B.); (T.A.G.); (M.T.); (P.L.); (M.R.)
- Correspondence: ; Tel.: +39-080-544-3604
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3
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Baumann L, Bruder S, Kabisch J, Boles E, Oreb M. High-Throughput Screening of an Octanoic Acid Producer Strain Library Enables Detection of New Targets for Increasing Titers in Saccharomyces cerevisiae. ACS Synth Biol 2021; 10:1077-1086. [PMID: 33979526 DOI: 10.1021/acssynbio.0c00600] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Octanoic acid is an industrially relevant compound with applications in antimicrobials or as a precursor for biofuels. Microbial biosynthesis through yeast is a promising alternative to current unsustainable production methods. To increase octanoic acid titers in Saccharomyces cerevisiae, we use a previously developed biosensor that is based on the octanoic acid responsive pPDR12 promotor coupled to GFP. We establish a biosensor strain amenable for high-throughput screening of an octanoic acid producer strain library. Through development, optimization, and execution of a high-throughput screening approach, we were able to detect two new genetic targets, KCS1 and FSH2, which increased octanoic acid titers through combined overexpression by about 55% compared to the parental strain. Neither target has yet been reported to be involved in fatty acid biosynthesis. The presented methodology can be employed to screen any genetic library and thereby more genes involved in improving octanoic acid production can be detected in the future.
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Affiliation(s)
- Leonie Baumann
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Stefan Bruder
- Department of Biology, Computer-aided Synthetic Biology, Technical University Darmstadt, Schnittspahnstr. 1, 64287 Darmstadt, Germany
| | - Johannes Kabisch
- Department of Biology, Computer-aided Synthetic Biology, Technical University Darmstadt, Schnittspahnstr. 1, 64287 Darmstadt, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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4
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Wernig F, Baumann L, Boles E, Oreb M. Production of octanoic acid in Saccharomyces cerevisiae: Investigation of new precursor supply engineering strategies and intrinsic limitations. Biotechnol Bioeng 2021; 118:3046-3057. [PMID: 34003487 DOI: 10.1002/bit.27814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/08/2021] [Accepted: 04/30/2021] [Indexed: 11/12/2022]
Abstract
The eight-carbon fatty acid octanoic acid (OA) is an important platform chemical and precursor of many industrially relevant products. Its microbial biosynthesis is regarded as a promising alternative to current unsustainable production methods. In Saccharomyces cerevisiae, the production of OA had been previously achieved by rational engineering of the fatty acid synthase. For the supply of the precursor molecule acetyl-CoA and of the redox cofactor NADPH, the native pyruvate dehydrogenase bypass had been harnessed, or the cells had been additionally provided with a pathway involving a heterologous ATP-citrate lyase. Here, we redirected the flux of glucose towards the oxidative branch of the pentose phosphate pathway and overexpressed a heterologous phosphoketolase/phosphotransacetylase shunt to improve the supply of NADPH and acetyl-CoA in a strain background with abolished OA degradation. We show that these modifications lead to an increased yield of OA during the consumption of glucose by more than 60% compared to the parental strain. Furthermore, we investigated different genetic engineering targets to identify potential factors that limit the OA production in yeast. Toxicity assays performed with the engineered strains suggest that the inhibitory effects of OA on cell growth likely impose an upper limit to attainable OA yields.
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Affiliation(s)
- Florian Wernig
- Department of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Leonie Baumann
- Department of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Eckhard Boles
- Department of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Mislav Oreb
- Department of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
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5
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Tamayo Rojas SA, Schmidl S, Boles E, Oreb M. Glucose-induced internalization of the S. cerevisiae galactose permease Gal2 is dependent on phosphorylation and ubiquitination of its aminoterminal cytoplasmic tail. FEMS Yeast Res 2021; 21:6206829. [PMID: 33791789 DOI: 10.1093/femsyr/foab019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/29/2021] [Indexed: 12/22/2022] Open
Abstract
The hexose permease Gal2 of Saccharomyces cerevisiae is expressed only in the presence of its physiological substrate galactose. Glucose tightly represses the GAL2 gene and also induces the clearance of the transporter from the plasma membrane by ubiquitination and subsequent degradation in the vacuole. Although many factors involved in this process, especially those responsible for the upstream signaling, have been elucidated, the mechanisms by which Gal2 is specifically targeted by the ubiquitination machinery have remained elusive. Here, we show that ubiquitination occurs within the N-terminal cytoplasmic tail and that the arrestin-like proteins Bul1 and Rod1 are likely acting as adaptors for docking of the ubiquitin E3-ligase Rsp5. We further demonstrate that phosphorylation on multiple residues within the tail is indispensable for the internalization and possibly represents a primary signal that might trigger the recruitment of arrestins to the transporter. In addition to these new fundamental insights, we describe Gal2 mutants with improved stability in the presence of glucose, which should prove valuable for engineering yeast strains utilizing complex carbohydrate mixtures present in hydrolysates of lignocellulosic or pectin-rich biomass.
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Affiliation(s)
- Sebastian A Tamayo Rojas
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, Frankfurt am Main 60438, Germany
| | - Sina Schmidl
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, Frankfurt am Main 60438, Germany
| | - Eckhard Boles
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, Frankfurt am Main 60438, Germany
| | - Mislav Oreb
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, Frankfurt am Main 60438, Germany
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6
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Schmidl S, Tamayo Rojas SA, Iancu CV, Choe JY, Oreb M. Functional Expression of the Human Glucose Transporters GLUT2 and GLUT3 in Yeast Offers Novel Screening Systems for GLUT-Targeting Drugs. Front Mol Biosci 2021; 7:598419. [PMID: 33681287 PMCID: PMC7930720 DOI: 10.3389/fmolb.2020.598419] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/23/2020] [Indexed: 01/31/2023] Open
Abstract
Human GLUT2 and GLUT3, members of the GLUT/SLC2 gene family, facilitate glucose transport in specific tissues. Their malfunction or misregulation is associated with serious diseases, including diabetes, metabolic syndrome, and cancer. Despite being promising drug targets, GLUTs have only a few specific inhibitors. To identify and characterize potential GLUT2 and GLUT3 ligands, we developed a whole-cell system based on a yeast strain deficient in hexose uptake, whose growth defect on glucose can be rescued by the functional expression of human transporters. The simplicity of handling yeast cells makes this platform convenient for screening potential GLUT2 and GLUT3 inhibitors in a growth-based manner, amenable to high-throughput approaches. Moreover, our expression system is less laborious for detailed kinetic characterization of inhibitors than alternative methods such as the preparation of proteoliposomes or uptake assays in Xenopus oocytes. We show that functional expression of GLUT2 in yeast requires the deletion of the extended extracellular loop connecting transmembrane domains TM1 and TM2, which appears to negatively affect the trafficking of the transporter in the heterologous expression system. Furthermore, single amino acid substitutions at specific positions of the transporter sequence appear to positively affect the functionality of both GLUT2 and GLUT3 in yeast. We show that these variants are sensitive to known inhibitors phloretin and quercetin, demonstrating the potential of our expression systems to significantly accelerate the discovery of compounds that modulate the hexose transport activity of GLUT2 and GLUT3.
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Affiliation(s)
- Sina Schmidl
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Sebastian A Tamayo Rojas
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States
| | - Jun-Yong Choe
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States.,Department of Biochemistry and Molecular Biology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
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7
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Baumann L, Doughty T, Siewers V, Nielsen J, Boles E, Oreb M. Transcriptomic response of Saccharomyces cerevisiae to octanoic acid production. FEMS Yeast Res 2021; 21:6144596. [PMID: 33599754 PMCID: PMC7972946 DOI: 10.1093/femsyr/foab011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
The medium-chain fatty acid octanoic acid is an important platform compound widely used in industry. The microbial production from sugars in Saccharomyces cerevisiae is a promising alternative to current non-sustainable production methods, however, titers need to be further increased. To achieve this, it is essential to have in-depth knowledge about the cell physiology during octanoic acid production. To this end, we collected the first RNA-Seq data of an octanoic acid producer strain at three time points during fermentation. The strain produced higher levels of octanoic acid and increased levels of fatty acids of other chain lengths (C6-C18) but showed decreased growth compared to the reference. Furthermore, we show that the here analyzed transcriptomic response to internally produced octanoic acid is notably distinct from a wild type's response to externally supplied octanoic acid as reported in previous publications. By comparing the transcriptomic response of different sampling times, we identified several genes that we subsequently overexpressed and knocked out, respectively. Hereby we identified RPL40B, to date unknown to play a role in fatty acid biosynthesis or medium-chain fatty acid tolerance. Overexpression of RPL40B led to an increase in octanoic acid titers by 40%.
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Affiliation(s)
- Leonie Baumann
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Tyler Doughty
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-41296 Gothenburg, Sweden
| | - Verena Siewers
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-41296 Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, SE-41296 Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE-41296 Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, SE-41296 Gothenburg, Sweden.,BioInnovation Institute, Ole Maaløes Vej 3, DK-2200 Copenhagen N, Denmark
| | - Eckhard Boles
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Faculty of Biological Sciences, Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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8
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Schmidl S, Iancu CV, Reifenrath M, Choe JY, Oreb M. A label-free real-time method for measuring glucose uptake kinetics in yeast. FEMS Yeast Res 2020; 21:6041724. [PMID: 33338229 DOI: 10.1093/femsyr/foaa069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/16/2020] [Indexed: 01/19/2023] Open
Abstract
Glucose uptake assays commonly rely on the isotope-labeled sugar, which is associated with radioactive waste and exposure of the experimenter to radiation. Here, we show that the rapid decrease of the cytosolic pH after a glucose pulse to starved Saccharomyces cerevisiae cells is dependent on the rate of sugar uptake and can be used to determine the kinetic parameters of sugar transporters. The pH-sensitive green fluorescent protein variant pHluorin is employed as a genetically encoded biosensor to measure the rate of acidification as a proxy of transport velocity in real time. The measurements are performed in the hexose transporter-deficient (hxt0) strain EBY.VW4000 that has been previously used to characterize a plethora of sugar transporters from various organisms. Therefore, this method provides an isotope-free, fluorometric approach for kinetic characterization of hexose transporters in a well-established yeast expression system.
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Affiliation(s)
- Sina Schmidl
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jun-Yong Choe
- Department of Chemistry, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC27834, USA
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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9
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Reifenrath M, Oreb M, Boles E, Tripp J. Artificial ER-Derived Vesicles as Synthetic Organelles for in Vivo Compartmentalization of Biochemical Pathways. ACS Synth Biol 2020; 9:2909-2916. [PMID: 33074655 DOI: 10.1021/acssynbio.0c00241] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Compartmentalization in membrane-surrounded organelles has the potential to overcome obstacles associated with the engineering of metabolic pathways, such as unwanted side reactions, accumulation of toxic intermediates, drain of intermediates out of the cell, and long diffusion distances. Strategies utilizing natural organelles suffer from the presence of endogenous pathways. In our approach, we make use of endoplasmic reticulum-derived vesicles loaded with enzymes of a metabolic pathway ("metabolic vesicles"). They are generated by fusion of synthetic peptides containing the N-terminal proline-rich and self-assembling region of the maize storage protein gamma-Zein ("Zera") to the pathway enzymes. We have applied a strategy to integrate three enzymes of a cis,cis-muconic acid production pathway into those vesicles in yeast. Using fluorescence microscopy and cell fractionation techniques, we have proven the formation of metabolic vesicles and the incorporation of enzymes. Activities of the enzymes and functionality of the compartmentalized pathway were demonstrated in fermentation experiments.
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Affiliation(s)
- Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
| | - Joanna Tripp
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
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10
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Schäfer D, Wagner J, Schmitz K, Benz J, Harth S, Oreb M, Weuster-Botz D. Two‐step bioprocess for
L
‐galactonate production from sugar beet pulp. CHEM-ING-TECH 2020. [DOI: 10.1002/cite.202055108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- D. Schäfer
- Technical University of Munich Biochemical Engineering Boltzmannstr. 15 85748 Garching Germany
| | - J. Wagner
- Technical University of Munich Biochemical Engineering Boltzmannstr. 15 85748 Garching Germany
| | - K. Schmitz
- Technical University of Munich Wood Bioprocesses Hans-Carl-von-Carlowitz-Platz 2 85354 Freising Germany
| | - J. P. Benz
- Technical University of Munich Wood Bioprocesses Hans-Carl-von-Carlowitz-Platz 2 85354 Freising Germany
| | - S. Harth
- Goethe University Frankfurt Molecular Biosciences Max-von-Laue-Str. 9 60438 Frankfurt am Main Germany
| | - M. Oreb
- Goethe University Frankfurt Molecular Biosciences Max-von-Laue-Str. 9 60438 Frankfurt am Main Germany
| | - D. Weuster-Botz
- Technical University of Munich Biochemical Engineering Boltzmannstr. 15 85748 Garching Germany
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11
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Zeug M, Markovic N, Iancu C, Tripp J, Oreb M, Choe J. The crystal structure of gallic acid decarboxylase from Arxula adeninivorans. Acta Crystallogr A Found Adv 2020. [DOI: 10.1107/s0108767320098232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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12
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Oreb M. Construction of artificial membrane transport metabolons – an emerging strategy in metabolic engineering. FEMS Microbiol Lett 2020; 367:5735437. [DOI: 10.1093/femsle/fnaa027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/11/2020] [Indexed: 12/18/2022] Open
Abstract
ABSTRACT
The term ‘membrane transport metabolon’ refers to the physical association of membrane transporters with enzymes that metabolize the transported substrates. In naturally evolved systems, physiological relevance of coupling transport with sequential enzymatic reactions resides, for instance, in faster turnover rates, protection of substrates from competing pathways or shielding the cellular environment from toxic compounds. Such underlying principles offer attractive possibilities for metabolic engineering approaches and concepts for constructing artificial transporter-enzyme complexes are recently being developed. In this minireview, the modes of substrate channeling across biological membranes and design principles for artificial transport metabolons are discussed.
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Affiliation(s)
- Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438 Frankfurt am Main, Germany
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13
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Gottardi M, Grün P, Bode HB, Hoffmann T, Schwab W, Oreb M, Boles E. Optimisation of trans-cinnamic acid and hydrocinnamyl alcohol production with recombinant Saccharomyces cerevisiae and identification of cinnamyl methyl ketone as a by-product. FEMS Yeast Res 2019; 17:4654848. [PMID: 29186481 DOI: 10.1093/femsyr/fox091] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/22/2017] [Indexed: 01/08/2023] Open
Abstract
Trans-cinnamic acid (tCA) and hydrocinnamyl alcohol (HcinOH) are valuable aromatic compounds with applications in the flavour, fragrance and cosmetic industry. They can be produced with recombinant yeasts from sugars via phenylalanine after expression of a phenylalanine ammonia lyase (PAL) and an aryl carboxylic acid reductase. Here, we show that in Saccharomyces cerevisiae a PAL enzyme from the bacterium Photorhabdus luminescens was superior to a previously used plant PAL enzyme for the production of tCA. Moreover, after expression of a UDP-glucose:cinnamate glucosyltransferase (FaGT2) from Fragaria x ananassa, tCA could be converted to cinnamoyl-D-glucose which is expected to be less toxic to the yeast cells. Production of tCA and HcinOH from glucose could be increased by eliminating feedback-regulated steps of aromatic amino acid biosynthesis and diminishing the decarboxylation step of the competing Ehrlich pathway. Finally, an unknown by-product resulting from further metabolisation of a carboligation product of cinnamaldehyde (cinALD) with activated acetaldehyde, mediated by pyruvate decarboxylases, could be identified as cinnamyl methyl ketone providing a new route for the biosynthesis of precursors, such as (2S,3R) 5-phenylpent-4-ene-2,3-diol, necessary for the chemical synthesis of specific biologically active drugs such as daunomycin.
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Affiliation(s)
- Manuela Gottardi
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Peter Grün
- Merck-Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - Helge B Bode
- Merck-Stiftungsprofessur für Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, 60438 Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Thomas Hoffmann
- Biotechnology of Natural Products, Technische Universität München, 85354 Freising, Germany
| | - Wilfried Schwab
- Biotechnology of Natural Products, Technische Universität München, 85354 Freising, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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Baumann L, Rajkumar AS, Morrissey JP, Boles E, Oreb M. A Yeast-Based Biosensor for Screening of Short- and Medium-Chain Fatty Acid Production. ACS Synth Biol 2018; 7:2640-2646. [PMID: 30338986 DOI: 10.1021/acssynbio.8b00309] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Short- and medium-chain fatty acids (SMCFA) are important platform chemicals currently produced from nonsustainable resources. The engineering of microbial cells to produce SMCFA, however, lacks high-throughput methods to screen for best performing cells. Here, we present the development of a whole-cell biosensor for easy and rapid detection of SMCFA. The biosensor is based on a multicopy yeast plasmid containing the SMCFA-responsive PDR12 promoter coupled to GFP as the reporter gene. The sensor detected hexanoic, heptanoic and octanoic acid over a linear range up to 2, 1.5, and 0.75 mM, respectively, but did not show a linear response to decanoic and dodecanoic acid. We validated the functionality of the biosensor with culture supernatants of a previously engineered Saccharomyces cerevisiae octanoic acid producer strain and derivatives thereof. The biosensor signal correlated strongly with the octanoic acid concentrations as determined by gas chromatography. Thus, this biosensor enables the high-throughput screening of SMCFA producers and has the potential to drastically speed up the engineering of diverse SMCFA producing cell factories.
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Affiliation(s)
- Leonie Baumann
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Arun S. Rajkumar
- School of Microbiology, Centre for Synthetic Biology and Biotechnology, Environmental Research Institute, APC Microbiome Institute, University College Cork, Cork T12 YN60, Ireland
| | - John P. Morrissey
- School of Microbiology, Centre for Synthetic Biology and Biotechnology, Environmental Research Institute, APC Microbiome Institute, University College Cork, Cork T12 YN60, Ireland
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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15
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Reifenrath M, Bauer M, Oreb M, Boles E. Bacterial bifunctional chorismate mutase-prephenate dehydratase PheA increases flux into the yeast phenylalanine pathway and improves mandelic acid production. Metab Eng Commun 2018; 7:e00079. [PMID: 30370221 PMCID: PMC6199770 DOI: 10.1016/j.mec.2018.e00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/21/2018] [Accepted: 09/17/2018] [Indexed: 01/29/2023] Open
Abstract
Mandelic acid is an important aromatic fine chemical and is currently mainly produced via chemical synthesis. Recently, mandelic acid production was achieved by microbial fermentations using engineered Escherichia coli and Saccharomyces cerevisiae expressing heterologous hydroxymandelate synthases (hmaS). The best-performing strains carried a deletion of the gene encoding the first enzyme of the tyrosine biosynthetic pathway and therefore were auxotrophic for tyrosine. This was necessary to avoid formation of the competing intermediate hydroxyphenylpyruvate, the preferred substrate for HmaS, which would have resulted in the predominant production of hydroxymandelic acid. However, feeding tyrosine to the medium would increase fermentation costs. In order to engineer a tyrosine prototrophic mandelic acid-producing S. cerevisiae strain, we tested three strategies: (1) rational engineering of the HmaS active site for reduced binding of hydroxyphenylpyruvate, (2) compartmentalization of the mandelic acid biosynthesis pathway by relocating HmaS together with the two upstream enzymes chorismate mutase Aro7 and prephenate dehydratase Pha2 into mitochondria or peroxisomes, and (3) utilizing a feedback-resistant version of the bifunctional E. coli enzyme PheA (PheAfbr) in an aro7 deletion strain. PheA has both chorismate mutase and prephenate dehydratase activity. Whereas the enzyme engineering approaches were only successful in respect to reducing the preference of HmaS for hydroxyphenylpyruvate but not in increasing mandelic acid titers, we could show that strategies (2) and (3) significantly reduced hydroxymandelic acid production in favor of increased mandelic acid production, without causing tyrosine auxotrophy. Using the bifunctional enzyme PheAfbr turned out to be the most promising strategy, and mandelic acid production could be increased 12-fold, yielding titers up to 120 mg/L. Moreover, our results indicate that utilizing PheAfbr also shows promise for other industrial applications with S. cerevisiae that depend on a strong flux into the phenylalanine biosynthetic pathway. Increased mandelic acid production in tyrosine prototrophic S. cerevisiae. Bifunctional E. coli enzyme PheA increases flux into yeast phenylalanine branch. PheA allows mandelic acid production in prototrophic S. cerevisiae. Compartmentalized mandelic acid production in yeast mitochondria/peroxisomes.
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Affiliation(s)
- Mara Reifenrath
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Maren Bauer
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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16
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Henritzi S, Fischer M, Grininger M, Oreb M, Boles E. An engineered fatty acid synthase combined with a carboxylic acid reductase enables de novo production of 1-octanol in Saccharomyces cerevisiae. Biotechnol Biofuels 2018; 11:150. [PMID: 29881455 PMCID: PMC5984327 DOI: 10.1186/s13068-018-1149-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/23/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND The ideal biofuel should not only be a regenerative fuel from renewable feedstocks, but should also be compatible with the existing fuel distribution infrastructure and with normal car engines. As the so-called drop-in biofuel, the fatty alcohol 1-octanol has been described as a valuable substitute for diesel and jet fuels and has already been produced fermentatively from sugars in small amounts with engineered bacteria via reduction of thioesterase-mediated premature release of octanoic acid from fatty acid synthase or via a reversal of the β-oxidation pathway. RESULTS The previously engineered short-chain acyl-CoA producing yeast Fas1R1834K/Fas2 fatty acid synthase variant was expressed together with carboxylic acid reductase from Mycobacterium marinum and phosphopantetheinyl transferase Sfp from Bacillus subtilis in a Saccharomyces cerevisiae Δfas1 Δfas2 Δfaa2 mutant strain. With the involvement of endogenous thioesterases, alcohol dehydrogenases, and aldehyde reductases, the synthesized octanoyl-CoA was converted to 1-octanol up to a titer of 26.0 mg L-1 in a 72-h fermentation. The additional accumulation of 90 mg L-1 octanoic acid in the medium indicated a bottleneck in 1-octanol production. When octanoic acid was supplied externally to the yeast cells, it could be efficiently converted to 1-octanol indicating that re-uptake of octanoic acid across the plasma membrane is not limiting. Additional overexpression of aldehyde reductase Ahr from Escherichia coli nearly completely prevented accumulation of octanoic acid and increased 1-octanol titers up to 49.5 mg L-1. However, in growth tests concentrations even lower than 50.0 mg L-1 turned out to be inhibitory to yeast growth. In situ extraction in a two-phase fermentation with dodecane as second phase did not improve growth, indicating that 1-octanol acts inhibitive before secretion. Furthermore, 1-octanol production was even reduced, which results from extraction of the intermediate octanoic acid to the organic phase, preventing its re-uptake. CONCLUSIONS By providing chain length control via an engineered octanoyl-CoA producing fatty acid synthase, we were able to specifically produce 1-octanol with S. cerevisiae. Before metabolic engineering can be used to further increase product titers and yields, strategies must be developed that cope with the toxic effects of 1-octanol on the yeast cells.
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Affiliation(s)
- Sandra Henritzi
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Manuel Fischer
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Cluster of Excellence “Macromolecular Complexes”, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Cluster of Excellence “Macromolecular Complexes”, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Mislav Oreb
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Eckhard Boles
- Faculty of Biological Sciences, Institute of Molecular Bioscience, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
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17
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Schmidl S, Iancu CV, Choe JY, Oreb M. Ligand Screening Systems for Human Glucose Transporters as Tools in Drug Discovery. Front Chem 2018; 6:183. [PMID: 29888221 PMCID: PMC5980966 DOI: 10.3389/fchem.2018.00183] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/07/2018] [Indexed: 12/22/2022] Open
Abstract
Hexoses are the major source of energy and carbon skeletons for biosynthetic processes in all kingdoms of life. Their cellular uptake is mediated by specialized transporters, including glucose transporters (GLUT, SLC2 gene family). Malfunction or altered expression pattern of GLUTs in humans is associated with several widespread diseases including cancer, diabetes and severe metabolic disorders. Their high relevance in the medical area makes these transporters valuable drug targets and potential biomarkers. Nevertheless, the lack of a suitable high-throughput screening system has impeded the determination of compounds that would enable specific manipulation of GLUTs so far. Availability of structural data on several GLUTs enabled in silico ligand screening, though limited by the fact that only two major conformations of the transporters can be tested. Recently, convenient high-throughput microbial and cell-free screening systems have been developed. These remarkable achievements set the foundation for further and detailed elucidation of the molecular mechanisms of glucose transport and will also lead to great progress in the discovery of GLUT effectors as therapeutic agents. In this mini-review, we focus on recent efforts to identify potential GLUT-targeting drugs, based on a combination of structural biology and different assay systems.
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Affiliation(s)
- Sina Schmidl
- Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
| | - Jun-Yong Choe
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
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18
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Varela JA, Montini N, Scully D, Van der Ploeg R, Oreb M, Boles E, Hirota J, Akada R, Hoshida H, Morrissey JP. Polymorphisms in the LAC12 gene explain lactose utilisation variability in Kluyveromyces marxianus strains. FEMS Yeast Res 2018; 17:3739724. [PMID: 28444380 DOI: 10.1093/femsyr/fox021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 04/16/2017] [Indexed: 01/29/2023] Open
Abstract
Kluyveromyces marxianus is a safe yeast used in the food and biotechnology sectors. One of the important traits that sets it apart from the familiar yeasts, Saccharomyces cerevisiae, is its capacity to grow using lactose as a carbon source. Like in its close relative, Kluyveromyces lactis, this requires lactose transport via a permease and intracellular hydrolysis of the disaccharide. Given the importance of the trait, it was intriguing that most, but not all, strains of K. marxianus are reported to consume lactose efficiently. In this study, primarily through heterologous expression in S. cerevisiae and K. marxianus, it was established that a single gene, LAC12, is responsible for lactose uptake in K. marxianus. Strains that failed to transport lactose showed variation in 13 amino acids in the Lac12p protein, rendering the protein non-functional for lactose transport. Genome analysis showed that the LAC12 gene is present in four copies in the subtelomeric regions of three different chromosomes but only the ancestral LAC12 gene encodes a functional lactose transporter. Other copies of LAC12 may be non-functional or have alternative substrates. The analysis raises some interesting questions regarding the evolution of sugar transporters in K. marxianus.
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Affiliation(s)
- Javier A Varela
- School of Microbiology, University College Cork, Cork T12YN60, Ireland
| | - Noemi Montini
- School of Microbiology, University College Cork, Cork T12YN60, Ireland
| | - Damhan Scully
- School of Microbiology, University College Cork, Cork T12YN60, Ireland
| | | | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Junya Hirota
- Department of Applied Chemistry, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan
| | - Rinji Akada
- Department of Applied Chemistry, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan.,Biomedical Engineering Center, Yamaguchi University, Ube 755-8611, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8315, Japan
| | - Hisashi Hoshida
- Department of Applied Chemistry, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube 755-8611, Japan.,Biomedical Engineering Center, Yamaguchi University, Ube 755-8611, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8315, Japan
| | - John P Morrissey
- School of Microbiology/Centre for Synthetic Biology and Biotechnology/Environmental Research Institute/APC Microbiome Institute, University College Cork, Cork T12 YN60, Ireland
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19
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Brückner C, Oreb M, Kunze G, Boles E, Tripp J. An expanded enzyme toolbox for production of cis, cis-muconic acid and other shikimate pathway derivatives in Saccharomyces cerevisiae. FEMS Yeast Res 2018; 18:4862472. [DOI: 10.1093/femsyr/foy017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/14/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Christine Brückner
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Gotthard Kunze
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466 Gatersleben, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Joanna Tripp
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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20
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Thomik T, Wittig I, Choe JY, Boles E, Oreb M. An artificial transport metabolon facilitates improved substrate utilization in yeast. Nat Chem Biol 2017; 13:1158-1163. [DOI: 10.1038/nchembio.2457] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 07/14/2017] [Indexed: 12/30/2022]
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21
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Tripp J, Essl C, Iancu CV, Boles E, Choe JY, Oreb M. Establishing a yeast-based screening system for discovery of human GLUT5 inhibitors and activators. Sci Rep 2017; 7:6197. [PMID: 28740135 PMCID: PMC5524692 DOI: 10.1038/s41598-017-06262-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/05/2017] [Indexed: 01/08/2023] Open
Abstract
Human GLUT5 is a fructose-specific transporter in the glucose transporter family (GLUT, SLC2 gene family). Its substrate-specificity and tissue-specific expression make it a promising target for treatment of diabetes, metabolic syndrome and cancer, but few GLUT5 inhibitors are known. To identify and characterize potential GLUT5 ligands, we developed a whole-cell system based on a yeast strain deficient in fructose uptake, in which GLUT5 transport activity is associated with cell growth in fructose-based media or assayed by fructose uptake in whole cells. The former method is convenient for high-throughput screening of potential GLUT5 inhibitors and activators, while the latter enables detailed kinetic characterization of identified GLUT5 ligands. We show that functional expression of GLUT5 in yeast requires mutations at specific positions of the transporter sequence. The mutated proteins exhibit kinetic properties similar to the wild-type transporter and are inhibited by established GLUT5 inhibitors N-[4-(methylsulfonyl)-2-nitrophenyl]-1,3-benzodioxol-5-amine (MSNBA) and (−)-epicatechin-gallate (ECG). Thus, this system has the potential to greatly accelerate the discovery of compounds that modulate the fructose transport activity of GLUT5.
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Affiliation(s)
- Joanna Tripp
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Christine Essl
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Cristina V Iancu
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL, 60064, USA
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany
| | - Jun-Yong Choe
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL, 60064, USA.
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438, Frankfurt am Main, Germany.
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22
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Generoso WC, Brinek M, Dietz H, Oreb M, Boles E. Secretion of 2,3-dihydroxyisovalerate as a limiting factor for isobutanol production in Saccharomyces cerevisiae. FEMS Yeast Res 2017; 17:3821180. [DOI: 10.1093/femsyr/fox029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 05/11/2017] [Indexed: 01/23/2023] Open
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23
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Varela JA, Montini N, Scully D, Van der Ploeg R, Oreb M, Boles E, Hirota J, Akada R, Hoshida H, Morrissey JP. Polymorphisms in the LAC12 gene explain lactose utilisation variability in Kluyveromyces marxianus strains. FEMS Yeast Res 2017. [DOI: 10.1093/femspd/fox021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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24
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Generoso WC, Gottardi M, Oreb M, Boles E. Simplified CRISPR-Cas genome editing for Saccharomyces cerevisiae. J Microbiol Methods 2016; 127:203-205. [DOI: 10.1016/j.mimet.2016.06.020] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 11/25/2022]
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25
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Jordan P, Choe JY, Boles E, Oreb M. Hxt13, Hxt15, Hxt16 and Hxt17 from Saccharomyces cerevisiae represent a novel type of polyol transporters. Sci Rep 2016; 6:23502. [PMID: 26996892 PMCID: PMC4800717 DOI: 10.1038/srep23502] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/09/2016] [Indexed: 12/03/2022] Open
Abstract
The genome of S. cerevisae encodes at least twenty hexose transporter-like proteins. Despite extensive research, the functions of Hxt8-Hxt17 have remained poorly defined. Here, we show that Hxt13, Hxt15, Hxt16 and Hxt17 transport two major hexitols in nature, mannitol and sorbitol, with moderate affinities, by a facilitative mechanism. Moreover, Hxt11 and Hxt15 are capable of transporting xylitol, a five-carbon polyol derived from xylose, the most abundant pentose in lignocellulosic biomass. Hxt11, Hxt13, Hxt15, Hxt16 and Hxt17 are phylogenetically and functionally distinct from known polyol transporters. Based on docking of polyols to homology models of transporters, we propose the architecture of their active site. In addition, we determined the kinetic parameters of mannitol and sorbitol dehydrogenases encoded in the yeast genome, showing that they discriminate between mannitol and sorbitol to a much higher degree than the transporters.
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Affiliation(s)
- Paulina Jordan
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Jun-Yong Choe
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL, 60064, USA
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University, Max-von-Laue Straße 9, 60438 Frankfurt am Main, Germany
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26
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Lumme C, Altan-Martin H, Dastvan R, Sommer MS, Oreb M, Schuetz D, Hellenkamp B, Mirus O, Kretschmer J, Lyubenova S, Kügel W, Medelnik JP, Dehmer M, Michaelis J, Prisner TF, Hugel T, Schleiff E. Nucleotides and substrates trigger the dynamics of the Toc34 GTPase homodimer involved in chloroplast preprotein translocation. Structure 2014; 22:526-38. [PMID: 24631462 DOI: 10.1016/j.str.2014.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/29/2014] [Accepted: 02/01/2014] [Indexed: 12/13/2022]
Abstract
GTPases are molecular switches that control numerous crucial cellular processes. Unlike bona fide GTPases, which are regulated by intramolecular structural transitions, the less well studied GAD-GTPases are activated by nucleotide-dependent dimerization. A member of this family is the translocase of the outer envelope membrane of chloroplast Toc34 involved in regulation of preprotein import. The GTPase cycle of Toc34 is considered a major circuit of translocation regulation. Contrary to expectations, previous studies yielded only marginal structural changes of dimeric Toc34 in response to different nucleotide loads. Referencing PELDOR and FRET single-molecule and bulk experiments, we describe a nucleotide-dependent transition of the dimer flexibility from a tight GDP- to a flexible GTP-loaded state. Substrate binding induces an opening of the GDP-loaded dimer. Thus, the structural dynamics of bona fide GTPases induced by GTP hydrolysis is replaced by substrate-dependent dimer flexibility, which likely represents a general regulatory mode for dimerizing GTPases.
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Affiliation(s)
- Christina Lumme
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Hasret Altan-Martin
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Reza Dastvan
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany; Department of Molecular Physiology & Biophysics, Vanderbilt University, 741 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Maik S Sommer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Mislav Oreb
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Denise Schuetz
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Björn Hellenkamp
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Oliver Mirus
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Jens Kretschmer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Sevdalina Lyubenova
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | | | - Jan P Medelnik
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | - Manuela Dehmer
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany
| | | | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Thorsten Hugel
- Physics Department E22 and IMETUM, Technical University Munich, 85748 Garching, Germany
| | - Enrico Schleiff
- Institute of Molecular Cell Biology of Plants, Goethe University, 60438 Frankfurt, Germany; Cluster of Excellence "Macromolecular Complexes", Goethe University, 60438 Frankfurt, Germany; Center for Membrane Proteomics, Goethe University, 60438 Frankfurt, Germany.
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27
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Farwick A, Bruder S, Schadeweg V, Oreb M, Boles E. Engineering of yeast hexose transporters to transport D-xylose without inhibition by D-glucose. Proc Natl Acad Sci U S A 2014; 111:5159-64. [PMID: 24706835 PMCID: PMC3986176 DOI: 10.1073/pnas.1323464111] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
All known D-xylose transporters are competitively inhibited by D-glucose, which is one of the major reasons hampering simultaneous fermentation of D-glucose and D-xylose, two primary sugars present in lignocellulosic biomass. We have set up a yeast growth-based screening system for mutant D-xylose transporters that are insensitive to the presence of D-glucose. All of the identified variants had a mutation at either a conserved asparagine residue in transmembrane helix 8 or a threonine residue in transmembrane helix 5. According to a homology model of the yeast hexose transporter Gal2 deduced from the crystal structure of the D-xylose transporter XylE from Escherichia coli, both residues are found in the same region of the protein and are positioned slightly to the extracellular side of the central sugar-binding pocket. Therefore, it is likely that alterations sterically prevent D-glucose but not D-xylose from entering the pocket. In contrast, changing amino acids that are supposed to directly interact with the C6 hydroxymethyl group of D-glucose negatively affected transport of both D-glucose and D-xylose. Determination of kinetic properties of the mutant transporters revealed that Gal2-N376F had the highest affinity for D-xylose, along with a moderate transport velocity, and had completely lost the ability to transport hexoses. These transporter versions should prove valuable for glucose-xylose cofermentation in lignocellulosic hydrolysates by Saccharomyces cerevisiae and other biotechnologically relevant organisms. Moreover, our data contribute to the mechanistic understanding of sugar transport because the decisive role of the conserved asparagine residue for determining sugar specificity has not been recognized before.
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Affiliation(s)
- Alexander Farwick
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Stefan Bruder
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Virginia Schadeweg
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Mislav Oreb
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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Linck A, Vu XK, Essl C, Hiesl C, Boles E, Oreb M. On the role of GAPDH isoenzymes during pentose fermentation in engineered Saccharomyces cerevisiae. FEMS Yeast Res 2014; 14:389-98. [PMID: 24456572 DOI: 10.1111/1567-1364.12137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 11/28/2022] Open
Abstract
In the metabolic network of the cell, many intermediary products are shared between different pathways. d-Glyceraldehyde-3-phosphate, a glycolytic intermediate, is a substrate of GAPDH but is also utilized by transaldolase and transketolase in the scrambling reactions of the nonoxidative pentose phosphate pathway. Recent efforts to engineer baker's yeast strains capable of utilizing pentose sugars present in plant biomass rely on increasing the carbon flux through this pathway. However, the competition between transaldolase and GAPDH for d-glyceraldehyde-3-phosphate produced in the first transketolase reaction compromises the carbon balance of the pathway, thereby limiting the product yield. Guided by the hypothesis that reduction in GAPDH activity would increase the availability of d-glyceraldehyde-3-phosphate for transaldolase and thereby improve ethanol production during fermentation of pentoses, we performed a comprehensive characterization of the three GAPDH isoenzymes in baker's yeast, Tdh1, Tdh2, and Tdh3 and analyzed the effect of their deletion on xylose utilization by engineered strains. Our data suggest that overexpression of transaldolase is a more promising strategy than reduction in GAPDH activity to increase the flux through the nonoxidative pentose phosphate pathway.
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Affiliation(s)
- Annabell Linck
- Institute for Molecular Bioscience, Goethe University, Frankfurt, Germany
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Oreb M, Dietz H, Farwick A, Boles E. Novel strategies to improve co-fermentation of pentoses with D-glucose by recombinant yeast strains in lignocellulosic hydrolysates. Bioengineered 2012; 3:347-51. [PMID: 22892590 PMCID: PMC3489712 DOI: 10.4161/bioe.21444] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Economically feasible production of second-generation biofuels requires efficient co-fermentation of pentose and hexose sugars in lignocellulosic hydrolysates under very harsh conditions. Baker’s yeast is an excellent, traditionally used ethanol producer but is naturally not able to utilize pentoses. This is due to the lack of pentose-specific transporter proteins and enzymatic reactions. Thus, natural yeast strains must be modified by genetic engineering. Although the construction of various recombinant yeast strains able to ferment pentose sugars has been described during the last two decades, their rates of pentose utilization is still significantly lower than D-glucose fermentation. Moreover, pentoses are only fermented after D-glucose is exhausted, resulting in an uneconomical increase in the fermentation time. In this addendum, we discuss novel approaches to improve utilization of pentoses by development of specific transporters and substrate channeling in enzyme cascades.
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Affiliation(s)
- Mislav Oreb
- Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany.
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Bionda T, Koenig P, Oreb M, Tews I, Schleiff E. pH Sensitivity of the GTPase Toc33 as a Regulatory Circuit for Protein Translocation into Chloroplasts. ACTA ACUST UNITED AC 2008; 49:1917-21. [DOI: 10.1093/pcp/pcn171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Abstract
Precursor protein translocation across the outer chloroplast membrane depends on the action of the Toc complex, containing GTPases as recognizing receptor components. The G domains of the GTPases are known to dimerize. In the dimeric conformation an arginine contacts the phosphate moieties of bound nucleotide in trans. Kinetic studies suggested that the arginine in itself does not act as an arginine finger of a reciprocal GTPase-activating protein (GAP). Here we investigate the specific function of the residue in two GTPase homologues. Arginine to alanine replacement variants have significantly reduced affinities for dimerization compared with wild-type GTPases. The amino acid exchange does not impact on the overall fold and nucleotide binding, as seen in the monomeric x-ray crystallographic structure of the Arabidopsis Toc33 arginine-alanine replacement variant at 2.0A. We probed the catalytic center with the transition state analogue GDP/AlF(x) using NMR and analytical ultracentrifugation. AlF(x) binding depends on the arginine, suggesting the residue can play a role in catalysis despite the non-GAP nature of the homodimer. Two non-exclusive functional models are discussed: 1) the coGAP hypothesis, in which an additional factor activates the GTPase in homodimeric form; and 2) the switch hypothesis, in which a protein, presumably the large Toc159 GTPase, exchanges with one of the homodimeric subunits, leading to activation.
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Affiliation(s)
- Patrick Koenig
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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Oreb M, Höfle A, Mirus O, Schleiff E. Phosphorylation regulates the assembly of chloroplast import machinery. J Exp Bot 2008; 59:2309-16. [PMID: 18487635 PMCID: PMC2423650 DOI: 10.1093/jxb/ern095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 03/06/2008] [Accepted: 03/10/2008] [Indexed: 05/24/2023]
Abstract
Chloroplast function depends on the translocation of cytosolically synthesized precursor proteins into the organelle. The recognition and transfer of most precursor proteins across the outer membrane depend on a membrane inserted complex. Two receptor components of this complex, Toc34 and Toc159, are GTPases, which can be phosphorylated by kinases present in the hosting membrane. However, the physiological function of phosphorylation is not yet understood in detail. It is demonstrated that both receptors are phosphorylated within their G-domains. In vitro, the phosphorylation of Toc34 disrupts both homo- and heterodimerization of the G-domains as determined using a phospho-mimicking mutant. In endogenous membranes this mutation or phosphorylation of the wild-type receptor disturbs the association of Toc34, but not of Toc159 with the translocation pore. Therefore, phosphorylation serves as an inhibitor for the association of Toc34 with other components of the complex and phosphorylation can now be discussed as a mechanism to exchange different isoforms of Toc34 within this ensemble.
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Affiliation(s)
| | | | | | - Enrico Schleiff
- Present address and to whom correspondence should be sent: Molecular Plant Sciences, Biocenter, N 200, 3. OG, Max-von-Laue-Str. 9, D-60438 Frankfurt/Main, Germany. E-mail:
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Koenig P, Oreb M, Höfle A, Kaltofen S, Rippe K, Sinning I, Schleiff E, Tews I. The GTPase cycle of the chloroplast import receptors Toc33/Toc34: implications from monomeric and dimeric structures. Structure 2008; 16:585-96. [PMID: 18400179 DOI: 10.1016/j.str.2008.01.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 01/18/2008] [Accepted: 01/22/2008] [Indexed: 11/18/2022]
Abstract
Transport of precursor proteins across chloroplast membranes involves the GTPases Toc33/34 and Toc159 at the outer chloroplast envelope. The small GTPase Toc33/34 can homodimerize, but the regulation of this interaction has remained elusive. We show that dimerization is independent of nucleotide loading state, based on crystal structures of dimeric Pisum sativum Toc34 and monomeric Arabidopsis thaliana Toc33. An arginine residue is--in the dimer--positioned to resemble a GAP arginine finger. However, GTPase activation by dimerization is sparse and active site features do not explain catalysis, suggesting that the homodimer requires an additional factor as coGAP. Access to the catalytic center and an unusual switch I movement in the dimeric structure support this finding. Potential binding sites for interactions within the Toc translocon or with precursor proteins can be derived from the structures.
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Affiliation(s)
- Patrick Koenig
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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Oreb M, Tews I, Schleiff E. Policing Tic 'n' Toc, the doorway to chloroplasts. Trends Cell Biol 2008; 18:19-27. [PMID: 18068366 DOI: 10.1016/j.tcb.2007.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/08/2007] [Accepted: 10/22/2007] [Indexed: 10/22/2022]
Abstract
The organization of eukaryotic cells into different membrane-enclosed compartments requires an ordered and regulated system for targeting and translocating proteins synthesized in the cytosol across organellar membranes. Protein translocation through integral membrane proteinaceous complexes shares common principles in different organelles, whereas molecular mechanisms and energy requirements are diverse. Translocation into mitochondria and plastids requires most proteins to cross two membranes, and translocation must be regulated to accommodate environmental or metabolic changes. In the last decade, the first ideas were formulated about the regulation of protein translocation into chloroplasts, thereby laying the foundation for this field. Here, we describe recent models for the regulation of translocation by precursor protein phosphorylation, receptor dimerization, redox sensing and calcium signaling. We suggest how these mechanisms might fit within the regulatory framework for the entry of proteins into chloroplasts.
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Affiliation(s)
- Mislav Oreb
- LMU München, Cluster of Excellence CIPS, Department of Biology I, Menziger Str. 67, 80638 München, Germany
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Oreb M, Zoryan M, Vojta A, Maier UG, Eichacker LA, Schleiff E. Phospho-mimicry mutant of atToc33 affects early development of Arabidopsis thaliana. FEBS Lett 2007; 581:5945-51. [DOI: 10.1016/j.febslet.2007.11.071] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 11/22/2007] [Indexed: 11/17/2022]
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Bittner F, Oreb M, Mendel RR. ABA3 is a molybdenum cofactor sulfurase required for activation of aldehyde oxidase and xanthine dehydrogenase in Arabidopsis thaliana. J Biol Chem 2001; 276:40381-4. [PMID: 11553608 DOI: 10.1074/jbc.c100472200] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The xanthine oxidase class of molybdenum enzyzmes requires a terminal sulfur ligand at the active site. It has been proposed that a special sulfurase catalyzes the insertion of this ligand thereby activating the enzymes. Previous analyses of mutants in plants indicated that the genetic locus aba3 is involved in this step leading to activation of the molybdenum enzymes aldehyde oxidase and xanthine dehydrogenase. Here we report the cloning of the aba3 gene from Arabidopsis thaliana and the biochemical characterization of the purified protein. ABA3 is a two-domain protein with a N-terminal NifS-like sulfurase domain and a C-terminal domain that might be involved in recognizing the target enzymes. Molecular analysis of three aba3 mutants identified mutations in both domains. ABA3 contains highly conserved binding motifs for pyridoxal phosphate and for a persulfide. The purified recombinant protein possesses a cysteine desulfurase activity, is yellow in color, and shows a NifS-like change in absorbance in the presence of L-cysteine. Pretreatment of ABA3 with a thiol-specific alkylating reagent inhibited its desulfurase activity. These data indicate a transsulfuration reaction similar to bacterial NifS. In a fully defined in vitro system, the purified protein was able to activate aldehyde oxidase by using L-cysteine as sulfur donor. Finally, we show that the expression of the aba3 gene is inducible by drought-stress.
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Affiliation(s)
- F Bittner
- Botanical Institute, Technical University of Braunschweig, 38023 Braunschweig, Germany
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