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Niederau PA, Eglé P, Willig S, Parsons J, Hoernstein SNW, Decker EL, Reski R. Multifactorial analysis of terminator performance on heterologous gene expression in Physcomitrella. PLANT CELL REPORTS 2024; 43:43. [PMID: 38246952 PMCID: PMC10800305 DOI: 10.1007/s00299-023-03088-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/02/2023] [Indexed: 01/23/2024]
Abstract
KEY MESSAGE Characterization of Physcomitrella 3'UTRs across different promoters yields endogenous single and double terminators for usage in molecular pharming. The production of recombinant proteins for health applications accounts for a large share of the biopharmaceutical market. While many drugs are produced in microbial and mammalian systems, plants gain more attention as expression hosts to produce eukaryotic proteins. In particular, the good manufacturing practice (GMP)-compliant moss Physcomitrella (Physcomitrium patens) has outstanding features, such as excellent genetic amenability, reproducible bioreactor cultivation, and humanized protein glycosylation patterns. In this study, we selected and characterized novel terminators for their effects on heterologous gene expression. The Physcomitrella genome contains 53,346 unique 3'UTRs (untranslated regions) of which 7964 transcripts contain at least one intron. Over 91% of 3'UTRs exhibit more than one polyadenylation site, indicating the prevalence of alternative polyadenylation in Physcomitrella. Out of all 3'UTRs, 14 terminator candidates were selected and characterized via transient Dual-Luciferase assays, yielding a collection of endogenous terminators performing equally high as established heterologous terminators CaMV35S, AtHSP90, and NOS. High performing candidates were selected for testing as double terminators which impact reporter levels, dependent on terminator identity and positioning. Testing of 3'UTRs among the different promoters NOS, CaMV35S, and PpActin5 showed an increase of more than 1000-fold between promoters PpActin5 and NOS, whereas terminators increased reporter levels by less than tenfold, demonstrating the stronger effect promoters play as compared to terminators. Among selected terminator attributes, the number of polyadenylation sites as well as polyadenylation signals were found to influence terminator performance the most. Our results improve the biotechnology platform Physcomitrella and further our understanding of how terminators influence gene expression in plants in general.
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Affiliation(s)
| | - Pauline Eglé
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sandro Willig
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
- Signalling Research Centre BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
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Ruiz-Molina N, Parsons J, Müller M, Hoernstein SNW, Bohlender LL, Pumple S, Zipfel PF, Häffner K, Reski R, Decker EL. A synthetic protein as efficient multitarget regulator against complement over-activation. Commun Biol 2022; 5:152. [PMID: 35194132 PMCID: PMC8863895 DOI: 10.1038/s42003-022-03094-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 02/01/2022] [Indexed: 11/09/2022] Open
Abstract
The complement system constitutes the innate defense against pathogens. Its dysregulation leads to diseases and is a critical determinant in many viral infections, e.g., COVID-19. Factor H (FH) is the main regulator of the alternative pathway of complement activation and could be a therapy to restore homeostasis. However, recombinant FH is not available. Engineered FH versions may be alternative therapeutics. Here, we designed a synthetic protein, MFHR13, as a multitarget complement regulator. It combines the dimerization and C5-regulatory domains of human FH-related protein 1 (FHR1) with the C3-regulatory and cell surface recognition domains of human FH, including SCR 13. In summary, the fusion protein MFHR13 comprises SCRs FHR11-2:FH1-4:FH13:FH19-20. It protects sheep erythrocytes from complement attack exhibiting 26 and 4-fold the regulatory activity of eculizumab and human FH, respectively. Furthermore, we demonstrate that MFHR13 and FHR1 bind to all proteins forming the membrane attack complex, which contributes to the mechanistic understanding of FHR1. We consider MFHR13 a promising candidate as therapeutic for complement-associated diseases. Ruiz-Molina et al. design a synthetic protein, MFHR13, as a multi-target complement regulator. They demonstrate that it protects sheep erythrocytes from complement attack exhibiting 26 and 4-fold the regulatory activity of eculizumab and human Factor H, respectively, which highlights its therapeutic potential.
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Affiliation(s)
- Natalia Ruiz-Molina
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Madeleine Müller
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Lennard L Bohlender
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Steffen Pumple
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Karsten Häffner
- Faculty of Medicine, Department of Internal Medicine IV, Medical Center, University of Freiburg, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
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3
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Rempfer C, Wiedemann G, Schween G, Kerres KL, Lucht JM, Horres R, Decker EL, Reski R. Autopolyploidization affects transcript patterns and gene targeting frequencies in Physcomitrella. PLANT CELL REPORTS 2022; 41:153-173. [PMID: 34636965 PMCID: PMC8803787 DOI: 10.1007/s00299-021-02794-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
In Physcomitrella, whole-genome duplications affected the expression of about 3.7% of the protein-encoding genes, some of them relevant for DNA repair, resulting in a massively reduced gene-targeting frequency. Qualitative changes in gene expression after an autopolyploidization event, a pure duplication of the whole genome (WGD), might be relevant for a different regulation of molecular mechanisms between angiosperms growing in a life cycle with a dominant diploid sporophytic stage and the haploid-dominant mosses. Whereas angiosperms repair DNA double-strand breaks (DSB) preferentially via non-homologous end joining (NHEJ), in the moss Physcomitrella homologous recombination (HR) is the main DNA-DSB repair pathway. HR facilitates the precise integration of foreign DNA into the genome via gene targeting (GT). Here, we studied the influence of ploidy on gene expression patterns and GT efficiency in Physcomitrella using haploid plants and autodiploid plants, generated via an artificial WGD. Single cells (protoplasts) were transfected with a GT construct and material from different time-points after transfection was analysed by microarrays and SuperSAGE sequencing. In the SuperSAGE data, we detected 3.7% of the Physcomitrella genes as differentially expressed in response to the WGD event. Among the differentially expressed genes involved in DNA-DSB repair was an upregulated gene encoding the X-ray repair cross-complementing protein 4 (XRCC4), a key player in NHEJ. Analysing the GT efficiency, we observed that autodiploid plants were significantly GT suppressed (p < 0.001) attaining only one third of the expected GT rates. Hence, an alteration of global transcript patterns, including genes related to DNA repair, in autodiploid Physcomitrella plants correlated with a drastic suppression of HR.
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Affiliation(s)
- Christine Rempfer
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany
| | - Gertrud Wiedemann
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
- Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - Gabriele Schween
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
- Corteva Agriscience, Pioneer Hi-Bred Northern Europe, Münstertäler Strasse 26, 79427, Eschbach, Germany
| | - Klaus L Kerres
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
| | - Jan M Lucht
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
- Scienceindustries, Nordstrasse 15, 8006, Zurich, Switzerland
| | - Ralf Horres
- GenXPro GmbH, Altenhöferallee 3, 60438, Frankfurt am Main, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany.
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany.
- Signalling Research Centres BIOSS and CIBSS, Schaenzlestr. 18, 79104, Freiburg, Germany.
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Top O, Milferstaedt SWL, van Gessel N, Hoernstein SNW, Özdemir B, Decker EL, Reski R. Expression of a human cDNA in moss results in spliced mRNAs and fragmentary protein isoforms. Commun Biol 2021; 4:964. [PMID: 34385580 PMCID: PMC8361020 DOI: 10.1038/s42003-021-02486-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 07/26/2021] [Indexed: 12/18/2022] Open
Abstract
Production of biopharmaceuticals relies on the expression of mammalian cDNAs in host organisms. Here we show that the expression of a human cDNA in the moss Physcomitrium patens generates the expected full-length and four additional transcripts due to unexpected splicing. This mRNA splicing results in non-functional protein isoforms, cellular misallocation of the proteins and low product yields. We integrated these results together with the results of our analysis of all 32,926 protein-encoding Physcomitrella genes and their 87,533 annotated transcripts in a web application, physCO, for automatized optimization. A thus optimized cDNA results in about twelve times more protein, which correctly localizes to the ER. An analysis of codon preferences of different production hosts suggests that similar effects occur also in non-plant hosts. We anticipate that the use of our methodology will prevent so far undetected mRNA heterosplicing resulting in maximized functional protein amounts for basic biology and biotechnology.
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Affiliation(s)
- Oguz Top
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
- Plant Molecular Cell Biology, Department Biology I, LMU Biocenter, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Stella W L Milferstaedt
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Cluster of Excellence livMatS @ FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg, Germany
| | - Nico van Gessel
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Bugra Özdemir
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.
- Cluster of Excellence livMatS @ FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg, Germany.
- CIBSS - Centre for Integrative Biological Signalling Studies, Freiburg, Germany.
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5
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Bohlender LL, Parsons J, Hoernstein SNW, Rempfer C, Ruiz-Molina N, Lorenz T, Rodríguez Jahnke F, Figl R, Fode B, Altmann F, Reski R, Decker EL. Stable Protein Sialylation in Physcomitrella. FRONTIERS IN PLANT SCIENCE 2020; 11:610032. [PMID: 33391325 PMCID: PMC7775405 DOI: 10.3389/fpls.2020.610032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/30/2020] [Indexed: 05/07/2023]
Abstract
Recombinantly produced proteins are indispensable tools for medical applications. Since the majority of them are glycoproteins, their N-glycosylation profiles are major determinants for their activity, structural properties and safety. For therapeutical applications, a glycosylation pattern adapted to product and treatment requirements is advantageous. Physcomitrium patens (Physcomitrella, moss) is able to perform highly homogeneous complex-type N-glycosylation. Additionally, it has been glyco-engineered to eliminate plant-specific sugar residues by knock-out of the β1,2-xylosyltransferase and α1,3-fucosyltransferase genes (Δxt/ft). Furthermore, Physcomitrella meets wide-ranging biopharmaceutical requirements such as GMP compliance, product safety, scalability and outstanding possibilities for precise genome engineering. However, all plants, in contrast to mammals, lack the capability to perform N-glycan sialylation. Since sialic acids are a common terminal modification on human N-glycans, the property to perform N-glycan sialylation is highly desired within the plant-based biopharmaceutical sector. In this study, we present the successful achievement of protein N-glycan sialylation in stably transformed Physcomitrella. The sialylation ability was achieved in a Δxt/ft moss line by stable expression of seven mammalian coding sequences combined with targeted organelle-specific localization of the encoded enzymes responsible for the generation of β1,4-galactosylated acceptor N-glycans as well as the synthesis, activation, transport and transfer of sialic acid. Production of free (Neu5Ac) and activated (CMP-Neu5Ac) sialic acid was proven. The glycosidic anchor for the attachment of terminal sialic acid was generated by the introduction of a chimeric human β1,4-galactosyltransferase gene under the simultaneous knock-out of the gene encoding the endogenous β1,3-galactosyltransferase. Functional complex-type N-glycan sialylation was confirmed via mass spectrometric analysis of a stably co-expressed recombinant human protein.
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Affiliation(s)
- Lennard L. Bohlender
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Christine Rempfer
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Natalia Ruiz-Molina
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Timo Lorenz
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Fernando Rodríguez Jahnke
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Rudolf Figl
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Friedrich Altmann
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
- Cluster of Excellence livMatS, Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Freiburg, Germany
| | - Eva L. Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- *Correspondence: Eva L. Decker,
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6
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Top O, Parsons J, Bohlender LL, Michelfelder S, Kopp P, Busch-Steenberg C, Hoernstein SNW, Zipfel PF, Häffner K, Reski R, Decker EL. Recombinant Production of MFHR1, A Novel Synthetic Multitarget Complement Inhibitor, in Moss Bioreactors. FRONTIERS IN PLANT SCIENCE 2019; 10:260. [PMID: 30949184 PMCID: PMC6436476 DOI: 10.3389/fpls.2019.00260] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/19/2019] [Indexed: 05/23/2023]
Abstract
The human complement system is an important part of the immune system responsible for lysis and elimination of invading microorganisms and apoptotic body cells. Improper activation of the system due to deficiency, mutations, or autoantibodies of complement regulators, mainly factor H (FH) and FH-related proteins (FHRs), causes severe kidney and eye diseases. However, there is no recombinant FH therapeutic available on the market. The first successful recombinant production of FH was accomplished with the moss bioreactor, Physcomitrella patens. Recently, a synthetic regulator, MFHR1, was designed to generate a multitarget complement inhibitor that combines the activities of FH and the FH-related protein 1 (FHR1). The potential of MFHR1 was demonstrated in a proof-of-concept study with transiently transfected insect cells. Here, we present the stable production of recombinant glyco-engineered MFHR1 in the moss bioreactor. The key features of this system are precise genome engineering via homologous recombination, Good Manufacturing Practice-compliant production in photobioreactors, high batch-to-batch reproducibility, and product stability. Several potential biopharmaceuticals are being produced in this system. In some cases, these are even biobetters, i.e., the recombinant proteins produced in moss have a superior quality compared to their counterparts from mammalian systems as for example moss-made aGal, which successfully passed phase I clinical trials. Via mass spectrometry-based analysis of moss-produced MFHR1, we now prove the correct synthesis and modification of this glycoprotein with predominantly complex-type N-glycan attachment. Moss-produced MFHR1 exhibits cofactor and decay acceleration activities comparable to FH, and its mechanism of action on multiple levels within the alternative pathway of complement activation led to a strong inhibitory activity on the whole alternative pathway, which was higher than with the physiological regulator FH.
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Affiliation(s)
- Oguz Top
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Juliana Parsons
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Lennard L. Bohlender
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Stefan Michelfelder
- Faculty of Medicine, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University Freiburg, University of Freiburg, Freiburg, Germany
| | - Phillipp Kopp
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | | | - Peter F. Zipfel
- Leibniz Institute for Natural Product Research and Infection Biology, Friedrich Schiller University, Jena, Germany
| | - Karsten Häffner
- Faculty of Medicine, Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University Freiburg, University of Freiburg, Freiburg, Germany
| | - Ralf Reski
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Eva L. Decker
- Department of Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany
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Reski R, Bae H, Simonsen HT. Physcomitrella patens, a versatile synthetic biology chassis. PLANT CELL REPORTS 2018; 37:1409-1417. [PMID: 29797047 DOI: 10.1007/s00299-018-2293-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/11/2018] [Indexed: 05/21/2023]
Abstract
During three decades the moss Physcomitrella patens has been developed to a superb green cell factory with the first commercial products on the market. In the past three decades the moss P. patens has been developed from an obscure bryophyte to a model organism in basic biology, biotechnology, and synthetic biology. Some of the key features of this system include a wide range of Omics technologies, precise genome-engineering via homologous recombination with yeast-like efficiency, a certified good-manufacturing-practice production in bioreactors, successful upscaling to 500 L wave reactors, excellent homogeneity of protein products, superb product stability from batch-to-batch, and a reliable procedure for cryopreservation of cell lines in a master cell bank. About a dozen human proteins are being produced in P. patens as potential biopharmaceuticals, some of them are not only similar to their animal-produced counterparts, but are real biobetters with superior performance. A moss-made pharmaceutical successfully passed phase 1 clinical trials, a fragrant moss, and a cosmetic moss-product is already on the market, highlighting the economic potential of this synthetic biology chassis. Here, we focus on the features of mosses as versatile cell factories for synthetic biology and their impact on metabolic engineering.
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Affiliation(s)
- Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.
- BIOSS, Centre for Biological Signalling Studies, 79104, Freiburg, Germany.
| | - Hansol Bae
- Mosspiration Biotech IVS, 2970, Hørsholm, Denmark
| | - Henrik Toft Simonsen
- Mosspiration Biotech IVS, 2970, Hørsholm, Denmark
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
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8
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Toplak M, Wiedemann G, Ulićević J, Daniel B, Hoernstein SNW, Kothe J, Niederhauser J, Reski R, Winkler A, Macheroux P. The single berberine bridge enzyme homolog of Physcomitrella patens is a cellobiose oxidase. FEBS J 2018; 285:1923-1943. [PMID: 29633551 PMCID: PMC6001459 DOI: 10.1111/febs.14458] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/17/2018] [Accepted: 03/29/2018] [Indexed: 11/28/2022]
Abstract
The berberine bridge enzyme from the California poppy Eschscholzia californica (EcBBE) catalyzes the oxidative cyclization of (S)‐reticuline to (S)‐scoulerine, that is, the formation of the berberine bridge in the biosynthesis of benzylisoquinoline alkaloids. Interestingly, a large number of BBE‐like genes have been identified in plants that lack alkaloid biosynthesis. This finding raised the question of the primordial role of BBE in the plant kingdom, which prompted us to investigate the closest relative of EcBBE in Physcomitrella patens (PpBBE1), the most basal plant harboring a BBE‐like gene. Here, we report the biochemical, structural, and in vivo characterization of PpBBE1. Our studies revealed that PpBBE1 is structurally and biochemically very similar to EcBBE. In contrast to EcBBE, we found that PpBBE1 catalyzes the oxidation of the disaccharide cellobiose to the corresponding lactone, that is, PpBBE1 is a cellobiose oxidase. The enzymatic reaction mechanism was characterized by a structure‐guided mutagenesis approach that enabled us to assign a catalytic role to amino acid residues in the active site of PpBBE1. In vivo experiments revealed the highest level of PpBBE1 expression in chloronema, the earliest stage of the plant's life cycle, where carbon metabolism is strongly upregulated. It was also shown that the enzyme is secreted to the extracellular space, where it may be involved in later steps of cellulose degradation, thereby allowing the moss to make use of cellulose for energy production. Overall, our results suggest that the primordial role of BBE‐like enzymes in plants revolved around primary metabolic reactions in carbohydrate utilization. Database Structural data are available in the PDB under the accession numbers 6EO4 and 6EO5.
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Affiliation(s)
- Marina Toplak
- Institute of Biochemistry, Graz University of Technology, Austria
| | - Gertrud Wiedemann
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Germany
| | - Jelena Ulićević
- Institute of Biochemistry, Graz University of Technology, Austria
| | - Bastian Daniel
- Institute of Biochemistry, Graz University of Technology, Austria
| | | | - Jennifer Kothe
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Germany
| | | | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Germany
| | - Andreas Winkler
- Institute of Biochemistry, Graz University of Technology, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Austria
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