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Nøkling-Eide K, Aachmann FL, Tøndervik A, Arlov Ø, Sletta H. In-process epimerisation of alginates from Saccharina latissima, Alaria esculenta and Laminaria hyperborea. Carbohydr Polym 2024; 325:121557. [PMID: 38008481 DOI: 10.1016/j.carbpol.2023.121557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 09/01/2023] [Revised: 10/17/2023] [Accepted: 11/01/2023] [Indexed: 11/28/2023]
Abstract
Alginates are valued in many industries, due to their versatile properties. These polysaccharides originate from brown algae (Phaeophyceae) and some bacteria of the Azotobacter and Pseudomonas genera, consisting of 1 → 4 linked β-d-mannuronic acid (M), and its C5-epimer α-l-guluronic acid (G). Several applications rely on a high G-content, which confers good gelling properties. Because of its high natural G-content (FG = 0.60-0.75), the alginate from Laminaria hyperborea (LH) has sustained a thriving industry in Norway. Alginates from other sources can be upgraded with mannuronan C-5 epimerases that convert M to G, and this has been demonstrated in many studies, but not applied in the seaweed industry. The present study demonstrates epimerisation directly in the process of alginate extraction from cultivated Saccharina latissima (SL) and Alaria esculenta (AE), and the lamina of LH. Unlike conventional epimerisation, which comprises multiple steps, this in-process protocol can decrease the time and costs necessary for alginate upgrading. In-process epimerisation with AlgE1 enzyme enhanced G-content and hydrogel strength in all examined species, with the greatest effect on SL (FG from 0.44 to 0.76, hydrogel Young's modulus from 22 to 34 kPa). As proof of concept, an upscaled in-process epimerisation of alginate from fresh SL was successfully demonstrated.
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Affiliation(s)
- Katharina Nøkling-Eide
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway; Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway.
| | - Finn Lillelund Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway
| | - Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway
| | - Øystein Arlov
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway
| | - Håvard Sletta
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3 B, 7034 Trondheim, Norway
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Pritchard MF, Powell LC, Adams JYM, Menzies G, Khan S, Tøndervik A, Sletta H, Aarstad O, Skjåk-Bræk G, McKenna S, Buurma NJ, Farnell DJJ, Rye PD, Hill KE, Thomas DW. Structure-Activity Relationships of Low Molecular Weight Alginate Oligosaccharide Therapy against Pseudomonas aeruginosa. Biomolecules 2023; 13:1366. [PMID: 37759766 PMCID: PMC10527064 DOI: 10.3390/biom13091366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 06/29/2023] [Revised: 08/26/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023] Open
Abstract
Low molecular weight alginate oligosaccharides have been shown to exhibit anti-microbial activity against a range of multi-drug resistant bacteria, including Pseudomonas aeruginosa. Previous studies suggested that the disruption of calcium (Ca2+)-DNA binding within bacterial biofilms and dysregulation of quorum sensing (QS) were key factors in these observed effects. To further investigate the contribution of Ca2+ binding, G-block (OligoG) and M-block alginate oligosaccharides (OligoM) with comparable average size DPn 19 but contrasting Ca2+ binding properties were prepared. Fourier-transform infrared spectroscopy demonstrated prolonged binding of alginate oligosaccharides to the pseudomonal cell membrane even after hydrodynamic shear treatment. Molecular dynamics simulations and isothermal titration calorimetry revealed that OligoG exhibited stronger interactions with bacterial LPS than OligoM, although this difference was not mirrored by differential reductions in bacterial growth. While confocal laser scanning microscopy showed that both agents demonstrated similar dose-dependent reductions in biofilm formation, OligoG exhibited a stronger QS inhibitory effect and increased potentiation of the antibiotic azithromycin in minimum inhibitory concentration and biofilm assays. This study demonstrates that the anti-microbial effects of alginate oligosaccharides are not purely influenced by Ca2+-dependent processes but also by electrostatic interactions that are common to both G-block and M-block structures.
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Affiliation(s)
- Manon F. Pritchard
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - Lydia C. Powell
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
- Microbiology and Infectious Disease Group, Swansea University Medical School, Swansea SA2 8PP, UK
| | - Jennifer Y. M. Adams
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - Georgina Menzies
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK;
| | - Saira Khan
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - Anne Tøndervik
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway; (A.T.); (H.S.)
| | - Håvard Sletta
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway; (A.T.); (H.S.)
| | - Olav Aarstad
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway; (O.A.); (G.S.-B.)
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway; (O.A.); (G.S.-B.)
| | - Stephen McKenna
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - Niklaas J. Buurma
- Physical Organic Chemistry Centre, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK;
| | - Damian J. J. Farnell
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - Philip D. Rye
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway;
| | - Katja E. Hill
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
| | - David W. Thomas
- Advanced Therapies Group, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK; (L.C.P.); (J.Y.M.A.); (S.K.); (S.M.); (D.J.J.F.); (K.E.H.); (D.W.T.)
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Madsen M, Prestel A, Madland E, Westh P, Tøndervik A, Sletta H, Peters GHJ, Aachmann FL, Kragelund BB, Svensson B. Molecular insights into alginate β-lactoglobulin A multivalencies-The foundation for their amorphous aggregates and coacervation. Protein Sci 2023; 32:e4556. [PMID: 36571497 PMCID: PMC9847093 DOI: 10.1002/pro.4556] [Citation(s) in RCA: 1] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/06/2022] [Accepted: 12/22/2022] [Indexed: 12/27/2022]
Abstract
For improved control of biomaterial property design, a better understanding of complex coacervation involving anionic polysaccharides and proteins is needed. Here, we address the initial steps in condensate formation of β-lactoglobulin A (β-LgA) with nine defined alginate oligosaccharides (AOSs) and describe their multivalent interactions in structural detail. Binding of AOSs containing four, five, or six uronic acid residues (UARs), either all mannuronate (M), all guluronate (G), or alternating M and G embodying the block structural components of alginates, was characterized by isothermal titration calorimetry, nuclear magnetic resonance spectroscopy (NMR), and molecular docking. β-LgA was highly multivalent exhibiting binding stoichiometries decreasing from five to two AOSs with increasing degree of polymerization (DP) and similar affinities in the mid micromolar range. The different AOS binding sites on β-LgA were identified by NMR chemical shift perturbation analyses and showed diverse compositions of charged, polar and hydrophobic residues. Distinct sites for the shorter AOSs merged to accommodate longer AOSs. The AOSs bound dynamically to β-LgA, as concluded from saturation transfer difference and 1 H-ligand-targeted NMR analyses. Molecular docking using Glide within the Schrödinger suite 2016-1 revealed the orientation of AOSs to only vary slightly at the preferred β-LgA binding site resulting in similar XP glide scores. The multivalency coupled with highly dynamic AOS binding with lack of confined conformations in the β-LgA complexes may help explain the first steps toward disordered β-LgA alginate coacervate structures.
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Affiliation(s)
- Mikkel Madsen
- Enzyme and Protein Chemistry, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Andreas Prestel
- Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagen NDenmark
| | - Eva Madland
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food ScienceNTNU Norwegian University of Science and TechnologyTrondheimNorway
| | - Peter Westh
- Interfacial Enzymology, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF IndustryTrondheimNorway
| | - Håvard Sletta
- Department of Biotechnology and Nanomedicine, SINTEF IndustryTrondheimNorway
| | - Günther H. J. Peters
- Biophysical and Biomedicinal Chemistry, Department of ChemistryTechnical University of DenmarkKgs. LyngbyDenmark
| | - Finn L. Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food ScienceNTNU Norwegian University of Science and TechnologyTrondheimNorway
| | - Birthe B. Kragelund
- Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagen NDenmark
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
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Haslene‐Hox H, Nærdal GK, Mørch Y, Hageskal G, Tøndervik A, Turøy AV, Johnsen H, Klinkenberg G, Sletta H. High-throughput assay for effect screening of amphotericin B and bioactive components on filamentous Candida albicans. J Appl Microbiol 2022; 133:3113-3125. [PMID: 35947058 PMCID: PMC9804330 DOI: 10.1111/jam.15770] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 04/28/2022] [Revised: 07/01/2022] [Accepted: 08/06/2022] [Indexed: 01/05/2023]
Abstract
AIMS The aim of this study was to develop a high-throughput robotic microtiter plate-based screening assay for Candida albicans, optimizing growth conditions to replicate the filamentous biofilm growth found in vivo, and subsequently, to demonstrate the assay by evaluating the effect of nutritional drinks alone and in combination with the antifungal amphotericin B (AmB). METHODS AND RESULTS Candida albicans cultured in a defined growth medium showed filamentous growth in microcolonies, mimicking the morphology of oral mucosal disease (oral candidiasis). Addition of nutrient drinks containing fruit juices, fish oil and whey protein to the medium resulted in changed morphology and promoted growth as free yeast cells and with weak biofilm structures. Minimum inhibitory concentration of AmB on the biofilms was 0.25 μg ml-1 , and this was eightfold reduced (0.0038 μg ml-1 ) in the presence of the nutritional drinks. CONCLUSIONS The established assay demonstrated applicability for screening of antifungal and anti-biofilm effects of bioactive substances on C. albicans biofilm with clinically relevant morphology. SIGNIFICANCE AND IMPACT OF THE STUDY Candida albicans is the causative agent of the majority of fungal infections globally. The filamentous morphology of C. albicans and the ability to form biofilm are traits known to increase virulence and resistance towards antifungals. This study describes the development of a plate-based in vitro screening method mimicking the filamentous morphology of C. albicans found in vivo. The assay established can thus facilitate efficient antifungal drug discovery and development.
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Affiliation(s)
- Hanne Haslene‐Hox
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Guro Kruge Nærdal
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Yrr Mørch
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Gunhild Hageskal
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Anne Tøndervik
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | | | - Heidi Johnsen
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Geir Klinkenberg
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
| | - Håvard Sletta
- Department of Biotechnology and NanomedicineSINTEF ASTrondheimNorway
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Tøndervik A, Aune R, Degelmann A, Piontek M, Ertesvåg H, Skjåk-Bræk G, Sletta H. Strain Construction and Process Development for Efficient Recombinant Production of Mannuronan C-5 Epimerases in Hansenula polymorpha. Front Plant Sci 2022; 13:837891. [PMID: 35734252 PMCID: PMC9208277 DOI: 10.3389/fpls.2022.837891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/08/2022] [Indexed: 06/15/2023]
Abstract
Alginates are linear polysaccharides produced by brown algae and some bacteria and are composed of β-D-mannuronic acid (M) and α-L-guluronic acid (G). Alginate has numerous present and potential future applications within industrial, medical and pharmaceutical areas and G rich alginates are traditionally most valuable and frequently used due to their gelling and viscosifying properties. Mannuronan C-5 epimerases are enzymes converting M to G at the polymer level during the biosynthesis of alginate. The Azotobacter vinelandii epimerases AlgE1-AlgE7 share a common structure, containing one or two catalytic A-modules (A), and one to seven regulatory R-modules (R). Despite the structural similarity of the epimerases, they create different M-G patterns in the alginate; AlgE4 (AR) creates strictly alternating MG structures whereas AlgE1 (ARRRAR) and AlgE6 (ARRR) create predominantly G-blocks. These enzymes are therefore promising tools for producing in vitro tailor-made alginates. Efficient in vitro epimerization of alginates requires availability of recombinantly produced alginate epimerases, and for this purpose the methylotrophic yeast Hansenula polymorpha is an attractive host organism. The present study investigates whether H. polymorpha is a suitable expression system for future large-scale production of AlgE1, AlgE4, and AlgE6. H. polymorpha expression strains were constructed using synthetic genes with reduced repetitive sequences as well as optimized codon usage. High cell density cultivations revealed that the largest epimerases AlgE1 (147 kDa) and AlgE6 (90 kDa) are subject to proteolytic degradation by proteases secreted by the yeast cells. However, degradation could be controlled to a large extent either by co-expression of chaperones or by adjusting cultivation conditions. The smaller AlgE4 (58 kDa) was stable under all tested conditions. The results obtained thus point toward a future potential for using H. polymorpha in industrial production of mannuronan C-5 epimerases for in vitro tailoring of alginates.
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Affiliation(s)
- Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Randi Aune
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | | | | | - Helga Ertesvåg
- Department of Biotechnology and Food Sciences, Trondheim, Norway
| | | | - Håvard Sletta
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
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Matica MA, Aachmann FL, Tøndervik A, Sletta H, Ostafe V. "Preparation, physico-chemical characterization and antibacterial properties of chitosan and chitosan–nisin membranes ". Studia UBB Chemia 2022. [DOI: 10.24193/subbchem.2022.1.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Gaardløs M, Samsonov SA, Sletmoen M, Hjørnevik M, Sætrom GI, Tøndervik A, Aachmann FL. Insights into the roles of charged residues in substrate binding and mode of action of mannuronan C-5 epimerase AlgE4. Glycobiology 2021; 31:1616-1635. [PMID: 33822050 DOI: 10.1093/glycob/cwab025] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/10/2021] [Indexed: 01/18/2023] Open
Abstract
Mannuronan C-5 epimerases catalyse the epimerization of monomer residues in the polysaccharide alginate, changing the physical properties of the biopolymer. The enzymes are utilized to tailor alginate to numerous biological functions by alginate-producing organisms. The underlying molecular mechanisms that control the processive movement of the epimerase along the substrate chain is still elusive. To study this, we have used an interdisciplinary approach combining molecular dynamics simulations with experimental methods from mutant studies of AlgE4, where initial epimerase activity and product formation were addressed with NMR spectroscopy, and characteristics of enzyme-substrate interactions were obtained with isothermal titration calorimetry and optical tweezers. Positive charges lining the substrate-binding groove of AlgE4 appear to control the initial binding of poly-mannuronate, and binding also seems to be mediated by both electrostatic and hydrophobic interactions. After the catalytic reaction, negatively charged enzyme residues might facilitate dissociation of alginate from the positive residues, working like electrostatic switches, allowing the substrate to translocate in the binding groove. Molecular simulations show translocation increments of two monosaccharide units before the next productive binding event resulting in MG-block formation, with the epimerase moving with its N-terminus towards the reducing end of the alginate chain. Our results indicate that the charge pair R343-D345 might be directly involved in conformational changes of a loop that can be important for binding and dissociation. The computational and experimental approaches used in this study complement each other, allowing for a better understanding of individual residues' roles in binding and movement along the alginate chains.
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Affiliation(s)
- Margrethe Gaardløs
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | | | - Marit Sletmoen
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Maya Hjørnevik
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Gerd Inger Sætrom
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
| | - Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands veg 3 B, N-7491 Trondheim, Norway
| | - Finn Lillelund Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, N-7491 Trondheim, Norway
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Tøndervik A, Aarstad OA, Aune R, Maleki S, Rye PD, Dessen A, Skjåk-Bræk G, Sletta H. Exploiting Mannuronan C-5 Epimerases in Commercial Alginate Production. Mar Drugs 2020; 18:E565. [PMID: 33218095 PMCID: PMC7698916 DOI: 10.3390/md18110565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/09/2020] [Accepted: 11/12/2020] [Indexed: 12/11/2022] Open
Abstract
Alginates are one of the major polysaccharide constituents of marine brown algae in commercial manufacturing. However, the content and composition of alginates differ according to the distinct parts of these macroalgae and have a direct impact on the concentration of guluronate and subsequent commercial value of the final product. The Azotobacter vinelandii mannuronan C-5 epimerases AlgE1 and AlgE4 were used to determine their potential value in tailoring the production of high guluronate low-molecular-weight alginates from two sources of high mannuronic acid alginates, the naturally occurring harvested brown algae (Ascophyllum nodosum, Durvillea potatorum, Laminaria hyperborea and Lessonia nigrescens) and a pure mannuronic acid alginate derived from fermented production of the mutant strain of Pseudomonas fluorescens NCIMB 10,525. The mannuronan C-5 epimerases used in this study increased the content of guluronate from 32% up to 81% in both the harvested seaweed and bacterial fermented alginate sources. The guluronate-rich alginate oligomers subsequently derived from these two different sources showed structural identity as determined by proton nuclear magnetic resonance (1H NMR), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and size-exclusion chromatography with online multi-angle static laser light scattering (SEC-MALS). Functional identity was determined by minimum inhibitory concentration (MIC) assays with selected bacteria and antibiotics using the previously documented low-molecular-weight guluronate enriched alginate OligoG CF-5/20 as a comparator. The alginates produced using either source showed similar antibiotic potentiation effects to the drug candidate OligoG CF-5/20 currently in development as a mucolytic and anti-biofilm agent. These findings clearly illustrate the value of using epimerases to provide an alternative production route for novel low-molecular-weight alginates.
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Affiliation(s)
- Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3B, N-7034 Trondheim, Norway; (R.A.); (S.M.); (H.S.)
| | - Olav A. Aarstad
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway; (O.A.A.); (G.S.-B.)
| | - Randi Aune
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3B, N-7034 Trondheim, Norway; (R.A.); (S.M.); (H.S.)
| | - Susan Maleki
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3B, N-7034 Trondheim, Norway; (R.A.); (S.M.); (H.S.)
| | - Philip D. Rye
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway; (P.D.R.); (A.D.)
| | - Arne Dessen
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway; (P.D.R.); (A.D.)
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway; (O.A.A.); (G.S.-B.)
| | - Håvard Sletta
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Richard Birkelands vei 3B, N-7034 Trondheim, Norway; (R.A.); (S.M.); (H.S.)
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9
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Stanisci A, Tøndervik A, Gaardløs M, Lervik A, Skjåk-Bræk G, Sletta H, Aachmann FL. Identification of a Pivotal Residue for Determining the Block Structure-Forming Properties of Alginate C-5 Epimerases. ACS Omega 2020; 5:4352-4361. [PMID: 32149266 PMCID: PMC7057702 DOI: 10.1021/acsomega.9b04490] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 02/11/2020] [Indexed: 05/13/2023]
Abstract
Alginate is a linear copolymer composed of 1→4 linked β-d-mannuronic acid (M) and its epimer α-l-guluronic acid (G). The polysaccharide is first produced as homopolymeric mannuronan and subsequently, at the polymer level, C-5 epimerases convert M residues to G residues. The bacterium Azotobacter vinelandii encodes a family of seven secreted and calcium ion-dependent mannuronan C-5 epimerases (AlgE1-AlgE7). These epimerases consist of two types of structural modules: the A-modules, which contain the catalytic site, and the R-modules, which influence activity through substrate and calcium binding. In this study, we rationally designed new hybrid mannuronan C-5 epimerases constituting the A-module from AlgE6 and the R-module from AlgE4. This led to a better understanding of the molecular mechanism determining differences in MG- and GG-block-forming properties of the enzymes. A long loop with either tyrosine or phenylalanine extruding from the β-helix of the enzyme proved essential in defining the final alginate block structure, probably by affecting substrate binding. Normal mode analysis of the A-module from AlgE6 supports the results.
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Affiliation(s)
- Annalucia Stanisci
- Department
of Biotechnology and Food Science, NTNU
Norwegian University of Science and Technology, Norwegian Biopolymer
Laboratory (NOBIPOL), Sem Sælands vei 6/8, NO 7491 Trondheim, Norway
| | - Anne Tøndervik
- Department
of Biotechnology and Nanomedicine, SINTEF
Industry, Richard Birkelands
veg 3 B, NO 7491 Trondheim, Norway
| | - Margrethe Gaardløs
- Department
of Biotechnology and Food Science, NTNU
Norwegian University of Science and Technology, Norwegian Biopolymer
Laboratory (NOBIPOL), Sem Sælands vei 6/8, NO 7491 Trondheim, Norway
| | - Anders Lervik
- Department
of Chemistry, NTNU Norwegian University
of Science and Technology, Høgskoleringen 5, NO 7491 Trondheim, Norway
| | - Gudmund Skjåk-Bræk
- Department
of Biotechnology and Food Science, NTNU
Norwegian University of Science and Technology, Norwegian Biopolymer
Laboratory (NOBIPOL), Sem Sælands vei 6/8, NO 7491 Trondheim, Norway
| | - Håvard Sletta
- Department
of Biotechnology and Nanomedicine, SINTEF
Industry, Richard Birkelands
veg 3 B, NO 7491 Trondheim, Norway
| | - Finn L. Aachmann
- Department
of Biotechnology and Food Science, NTNU
Norwegian University of Science and Technology, Norwegian Biopolymer
Laboratory (NOBIPOL), Sem Sælands vei 6/8, NO 7491 Trondheim, Norway
- E-mail: . Phone: +4773593317. Fax: +4773591283
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Mærk M, Jakobsen ØM, Sletta H, Klinkenberg G, Tøndervik A, Ellingsen TE, Valla S, Ertesvåg H. Identification of Regulatory Genes and Metabolic Processes Important for Alginate Biosynthesis in Azotobacter vinelandii by Screening of a Transposon Insertion Mutant Library. Front Bioeng Biotechnol 2020; 7:475. [PMID: 32010681 PMCID: PMC6979010 DOI: 10.3389/fbioe.2019.00475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 10/07/2019] [Accepted: 12/23/2019] [Indexed: 12/23/2022] Open
Abstract
Azotobacter vinelandii produces the biopolymer alginate, which has a wide range of industrial and pharmaceutical applications. A random transposon insertion mutant library was constructed from A. vinelandii ATCC12518Tc in order to identify genes and pathways affecting alginate biosynthesis, and about 4,000 mutant strains were screened for altered alginate production. One mutant, containing a mucA disruption, displayed an elevated alginate production level, and several mutants with decreased or abolished alginate production were identified. The regulatory proteins AlgW and AmrZ seem to be required for alginate production in A. vinelandii, similarly to Pseudomonas aeruginosa. An algB mutation did however not affect alginate yield in A. vinelandii although its P. aeruginosa homolog is needed for full alginate production. Inactivation of the fructose phosphoenolpyruvate phosphotransferase system protein FruA resulted in a mutant that did not produce alginate when cultivated in media containing various carbon sources, indicating that this system could have a role in regulation of alginate biosynthesis. Furthermore, impaired or abolished alginate production was observed for strains with disruptions of genes involved in peptidoglycan biosynthesis/recycling and biosynthesis of purines, isoprenoids, TCA cycle intermediates, and various vitamins, suggesting that sufficient access to some of these compounds is important for alginate production. This hypothesis was verified by showing that addition of thiamine, succinate or a mixture of lysine, methionine and diaminopimelate increases alginate yield in the non-mutagenized strain. These results might be used in development of optimized alginate production media or in genetic engineering of A. vinelandii strains for alginate bioproduction.
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Affiliation(s)
- Mali Mærk
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | | | | | | | - Svein Valla
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Helga Ertesvåg
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
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Matica MA, Aachmann FL, Tøndervik A, Sletta H, Ostafe V. Chitosan as a Wound Dressing Starting Material: Antimicrobial Properties and Mode of Action. Int J Mol Sci 2019; 20:E5889. [PMID: 31771245 PMCID: PMC6928789 DOI: 10.3390/ijms20235889] [Citation(s) in RCA: 309] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/19/2019] [Accepted: 11/21/2019] [Indexed: 02/07/2023] Open
Abstract
Fighting bacterial resistance is one of the concerns in modern days, as antibiotics remain the main resource of bacterial control. Data shows that for every antibiotic developed, there is a microorganism that becomes resistant to it. Natural polymers, as the source of antibacterial agents, offer a new way to fight bacterial infection. The advantage over conventional synthetic antibiotics is that natural antimicrobial agents are biocompatible, non-toxic, and inexpensive. Chitosan is one of the natural polymers that represent a very promising source for the development of antimicrobial agents. In addition, chitosan is biodegradable, non-toxic, and most importantly, promotes wound healing, features that makes it suitable as a starting material for wound dressings. This paper reviews the antimicrobial properties of chitosan and describes the mechanisms of action toward microbial cells as well as the interactions with mammalian cells in terms of wound healing process. Finally, the applications of chitosan as a wound-dressing material are discussed along with the current status of chitosan-based wound dressings existing on the market.
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Affiliation(s)
- Mariana Adina Matica
- Advanced Environmental Research Laboratories, Department of Biology—Chemistry, West University of Timisoara, Oituz 4, 300086 Timisoara, Romania;
| | - Finn Lillelund Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food Sciences, NTNU Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway;
| | - Anne Tøndervik
- SINTEF Industry, Department of Biotechnology and Nanomedicine, Richard Birkelands veg 3 B, 7034 Trondheim, Norway; (A.T.); (H.S.)
| | - Håvard Sletta
- SINTEF Industry, Department of Biotechnology and Nanomedicine, Richard Birkelands veg 3 B, 7034 Trondheim, Norway; (A.T.); (H.S.)
| | - Vasile Ostafe
- Advanced Environmental Research Laboratories, Department of Biology—Chemistry, West University of Timisoara, Oituz 4, 300086 Timisoara, Romania;
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Aarstad OA, Stanisci A, Sætrom GI, Tøndervik A, Sletta H, Aachmann FL, Skjåk-Bræk G. Biosynthesis and Function of Long Guluronic Acid-Blocks in Alginate Produced by Azotobacter vinelandii. Biomacromolecules 2019; 20:1613-1622. [DOI: 10.1021/acs.biomac.8b01796] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Olav Andreas Aarstad
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway
| | - Annalucia Stanisci
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway
| | - Gerd Inger Sætrom
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway
| | - Anne Tøndervik
- SINTEF Industry, Department of Biotechnology and Nanomedicine, Richard Birkelands vei 3B, 7034 Trondheim, Norway
| | - Håvard Sletta
- SINTEF Industry, Department of Biotechnology and Nanomedicine, Richard Birkelands vei 3B, 7034 Trondheim, Norway
| | - Finn Lillelund Aachmann
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 6-8, N-7491 Trondheim, Norway
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Stanisci A, Aarstad OA, Tøndervik A, Sletta H, Dypås LB, Skjåk-Bræk G, Aachmann FL. Overall size of mannuronan C5-Epimerases influences their ability to epimerize modified alginates and alginate gels. Carbohydr Polym 2018; 180:256-263. [DOI: 10.1016/j.carbpol.2017.09.094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/11/2017] [Accepted: 09/27/2017] [Indexed: 10/18/2022]
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Eide KB, Stockinger LW, Lewin AS, Tøndervik A, Eijsink VG, Sørlie M. The role of active site aromatic residues in substrate degradation by the human chitotriosidase. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2016; 1864:242-7. [DOI: 10.1016/j.bbapap.2015.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 11/15/2022]
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Stockinger LW, Eide KB, Dybvik AI, Sletta H, Vårum KM, Eijsink VG, Tøndervik A, Sørlie M. The effect of the carbohydrate binding module on substrate degradation by the human chitotriosidase. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2015; 1854:1494-501. [DOI: 10.1016/j.bbapap.2015.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/29/2015] [Accepted: 06/23/2015] [Indexed: 11/25/2022]
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Tøndervik A, Sletta H, Klinkenberg G, Emanuel C, Powell LC, Pritchard MF, Khan S, Craine KM, Onsøyen E, Rye PD, Wright C, Thomas DW, Hill KE. Alginate oligosaccharides inhibit fungal cell growth and potentiate the activity of antifungals against Candida and Aspergillus spp. PLoS One 2014; 9:e112518. [PMID: 25409186 PMCID: PMC4237368 DOI: 10.1371/journal.pone.0112518] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 10/03/2014] [Indexed: 12/24/2022] Open
Abstract
The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD600; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity.
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Affiliation(s)
- Anne Tøndervik
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Håvard Sletta
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
- * E-mail:
| | - Geir Klinkenberg
- Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Charlotte Emanuel
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Lydia C. Powell
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Manon F. Pritchard
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Saira Khan
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Kieron M. Craine
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Edvar Onsøyen
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway
| | - Phil D. Rye
- AlgiPharma AS, Industriveien 33, N-1337 Sandvika, Norway
| | - Chris Wright
- Centre for NanoHealth, Systems and Process Engineering Centre, College of Engineering, Swansea University, Swansea, SA2 8PP, United Kingdom
| | - David W. Thomas
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
| | - Katja E. Hill
- Advanced Therapies Group, Tissue Engineering and Reparative Dentistry, Cardiff University School of Dentistry, Cardiff, CF14 4XY, United Kingdom
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Buchinger E, Knudsen DH, Behrens MA, Pedersen JS, Aarstad OA, Tøndervik A, Valla S, Skjåk-Bræk G, Wimmer R, Aachmann FL. Structural and functional characterization of the R-modules in alginate C-5 epimerases AlgE4 and AlgE6 from Azotobacter vinelandii. J Biol Chem 2014; 289:31382-96. [PMID: 25266718 DOI: 10.1074/jbc.m114.567008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [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: 01/08/2023] Open
Abstract
The bacterium Azotobacter vinelandii produces a family of seven secreted and calcium-dependent mannuronan C-5 epimerases (AlgE1-7). These epimerases are responsible for the epimerization of β-D-mannuronic acid (M) to α-L-guluronic acid (G) in alginate polymers. The epimerases display a modular structure composed of one or two catalytic A-modules and from one to seven R-modules having an activating effect on the A-module. In this study, we have determined the NMR structure of the three individual R-modules from AlgE6 (AR1R2R3) and the overall structure of both AlgE4 (AR) and AlgE6 using small angle x-ray scattering. Furthermore, the alginate binding ability of the R-modules of AlgE4 and AlgE6 has been studied with NMR and isothermal titration calorimetry. The AlgE6 R-modules fold into an elongated parallel β-roll with a shallow, positively charged groove across the module. Small angle x-ray scattering analyses of AlgE4 and AlgE6 show an overall elongated shape with some degree of flexibility between the modules for both enzymes. Titration of the R-modules with defined alginate oligomers shows strong interaction between AlgE4R and both oligo-M and MG, whereas no interaction was detected between these oligomers and the individual R-modules from AlgE6. A combination of all three R-modules from AlgE6 shows weak interaction with long M-oligomers. Exchanging the R-modules between AlgE4 and AlgE6 resulted in a novel epimerase called AlgE64 with increased G-block forming ability compared with AlgE6.
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Affiliation(s)
- Edith Buchinger
- From the Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Frederik Bajers vej 7H, DK-9220 Aalborg, Denmark, the Department of Biotechnology, Norwegian Biopolymer Laboratory (NOBIPOL), Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway
| | - Daniel H Knudsen
- From the Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Frederik Bajers vej 7H, DK-9220 Aalborg, Denmark
| | - Manja A Behrens
- the Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000, Denmark, and
| | - Jan Skov Pedersen
- the Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000, Denmark, and
| | - Olav A Aarstad
- the Department of Biotechnology, Norwegian Biopolymer Laboratory (NOBIPOL), Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway
| | - Anne Tøndervik
- the Department of Bioprocess Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Svein Valla
- the Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000, Denmark, and
| | - Gudmund Skjåk-Bræk
- the Department of Biotechnology, Norwegian Biopolymer Laboratory (NOBIPOL), Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway
| | - Reinhard Wimmer
- From the Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Frederik Bajers vej 7H, DK-9220 Aalborg, Denmark
| | - Finn L Aachmann
- the Department of Biotechnology, Norwegian Biopolymer Laboratory (NOBIPOL), Norwegian University of Science and Technology, Sem Sælands vei 6/8, 7491 Trondheim, Norway,
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Tøndervik A, Klinkenberg G, Aachmann FL, Svanem BIG, Ertesvåg H, Ellingsen TE, Valla S, Skjåk-Bræk G, Sletta H. Mannuronan C-5 Epimerases Suited for Tailoring of Specific Alginate Structures Obtained by High-Throughput Screening of an Epimerase Mutant Library. Biomacromolecules 2013; 14:2657-66. [DOI: 10.1021/bm4005194] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anne Tøndervik
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Geir Klinkenberg
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Finn L. Aachmann
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491
Trondheim, Norway
| | - Britt Iren Glærum Svanem
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491
Trondheim, Norway
| | - Helga Ertesvåg
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491
Trondheim, Norway
| | - Trond E. Ellingsen
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Svein Valla
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491
Trondheim, Norway
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology, Norwegian University of Science and Technology, N-7491
Trondheim, Norway
| | - Håvard Sletta
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
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Stenvik J, Sletta H, Grimstad Ø, Pukstad B, Ryan L, Aune R, Strand W, Tøndervik A, Helge Torp S, Skjåk-Braek G, Espevik T. Alginates induce differentiation and expression of CXCR7 and CXCL12/SDF-1 in human keratinocytes-The role of calcium. J Biomed Mater Res A 2012; 100:2803-12. [DOI: 10.1002/jbm.a.34219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 03/26/2012] [Accepted: 04/05/2012] [Indexed: 01/16/2023]
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Tøndervik A, Bruheim P, Berg L, Ellingsen TE, Kotlar HK, Valla S, Throne-Holst M. Ralstonia sp. U2 naphthalene dioxygenase and Comamonas sp. JS765 nitrobenzene dioxygenase show differences in activity towards methylated naphthalenes. J Biosci Bioeng 2012; 113:173-8. [DOI: 10.1016/j.jbiosc.2011.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/28/2011] [Accepted: 10/02/2011] [Indexed: 11/26/2022]
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Aarstad OA, Tøndervik A, Sletta H, Skjåk-Bræk G. Alginate Sequencing: An Analysis of Block Distribution in Alginates Using Specific Alginate Degrading Enzymes. Biomacromolecules 2011; 13:106-16. [DOI: 10.1021/bm2013026] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olav Andreas Aarstad
- Department of Biotechnology, Norwegian University of Science and Technology, NTNU
Sem Sælands vei 6-8, N-7491 Trondheim, Norway
| | - Anne Tøndervik
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Håvard Sletta
- Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Gudmund Skjåk-Bræk
- Department of Biotechnology, Norwegian University of Science and Technology, NTNU
Sem Sælands vei 6-8, N-7491 Trondheim, Norway
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22
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Tøndervik A, Klinkenberg G, Aarstad OA, Drabløs F, Ertesvåg H, Ellingsen TE, Skjåk-Bræk G, Valla S, Sletta H. Isolation of mutant alginate lyases with cleavage specificity for di-guluronic acid linkages. J Biol Chem 2010; 285:35284-92. [PMID: 20826807 PMCID: PMC2975152 DOI: 10.1074/jbc.m110.162800] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [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] [Received: 07/21/2010] [Revised: 09/01/2010] [Indexed: 11/06/2022] Open
Abstract
Alginates are commercially valuable and complex polysaccharides composed of varying amounts and distribution patterns of 1-4-linked β-D-mannuronic acid (M) and α-L-guluronic acid (G). This structural variability strongly affects polymer physicochemical properties and thereby both commercial applications and biological functions. One promising approach to alginate fine structure elucidation involves the use of alginate lyases, which degrade the polysaccharide by cleaving the glycosidic linkages through a β-elimination reaction. For such studies one would ideally like to have different lyases, each of which cleaves only one of the four possible linkages in alginates: G-G, G-M, M-G, and M-M. So far no lyase specific for only G-G linkages has been described, and here we report the construction of such an enzyme by mutating the gene encoding Klebsiella pneumoniae lyase AlyA (a polysaccharide lyase family 7 lyase), which cleaves both G-G and G-M linkages. After error-prone PCR mutagenesis and high throughput screening of ∼7000 lyase mutants, enzyme variants with a strongly improved G-G specificity were identified. Furthermore, in the absence of Ca(2+), one of these lyases (AlyA5) was found to display no detectable activity against G-M linkages. G-G linkages were cleaved with ∼10% of the optimal activity under the same conditions. The substitutions conferring altered specificity to the mutant enzymes are located in conserved regions in the polysaccharide lyase family 7 alginate lyases. Structure-function analyses by comparison with the known three-dimensional structure of Sphingomonas sp. A1 lyase A1-II' suggests that the improved G-G specificity might be caused by increased affinity for nonproductive binding of the alternating G-M structure.
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Affiliation(s)
- Anne Tøndervik
- From the Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway and
- the Departments of Biotechnology and
| | - Geir Klinkenberg
- From the Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway and
| | | | - Finn Drabløs
- Cancer Research and Molecular Medicine, The Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | | | - Trond E. Ellingsen
- From the Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway and
| | | | | | - Håvard Sletta
- From the Department of Biotechnology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway and
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Tøndervik A, Strøm AR. Membrane topology and mutational analysis of the osmotically activated BetT choline transporter of Escherichia coli. Microbiology (Reading) 2007; 153:803-813. [PMID: 17322201 DOI: 10.1099/mic.0.2006/003608-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
For osmoprotection, Escherichia coli can synthesize glycine betaine from externally supplied choline by the Bet system (betTIBA products). The major carrier of choline is the high-affinity, proton-driven, secondary transporter BetT, which belongs to the BCCT family of transporters. Fusion proteins consisting of N-terminal fragments of BetT linked to beta-galactosidase (LacZ) or alkaline phosphatase (PhoA) were constructed. By analysis of 51 fusion proteins with 37 unique fusion-points, the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed. This is believed to represent the first experimental examination of the membrane topology of a BCCT family protein. Osmotic upshock experiments were performed with spectinomycin-treated E. coli cells that had expressed the wild-type or a mutant BetT protein during growth at low osmolality (160 mosmol kg(-1)). The choline transport activity of wild-type BetT increased tenfold when the cells were stressed with 0.4 M NaCl (total osmolality 780 mosmol kg(-1)). The peak activity was recorded 5 min after the upshock and higher or lower concentrations of NaCl reduced the activity. Deletions of 1-12 C-terminal residues of BetT caused a gradual reduction in the degree of osmotic activation from ten- to twofold. Mutant proteins with deletion of 18-101 residues displayed a background transport activity, but they could not be osmotically activated. The data showed that the cytoplasmic C-terminal domain of BetT plays an important role in the regulation of BetT activity and that C-terminal truncations can cause BetT to be permanently locked in a low-transport-activity mode.
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Affiliation(s)
- Anne Tøndervik
- Department of Biotechnology, The Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - Arne R Strøm
- Department of Biotechnology, The Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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Sletta H, Tøndervik A, Hakvåg S, Aune TEV, Nedal A, Aune R, Evensen G, Valla S, Ellingsen TE, Brautaset T. The presence of N-terminal secretion signal sequences leads to strong stimulation of the total expression levels of three tested medically important proteins during high-cell-density cultivations of Escherichia coli. Appl Environ Microbiol 2006; 73:906-12. [PMID: 17142370 PMCID: PMC1800768 DOI: 10.1128/aem.01804-06] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [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: 11/20/2022] Open
Abstract
Genetic optimizations to achieve high-level production of three different proteins of medical importance for humans, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon alpha 2b (IFN-alpha2b), and single-chain antibody variable fragment (scFv-phOx), were investigated during high-cell-density cultivations of Escherichia coli. All three proteins were poorly expressed when put under control of the strong Pm/xylS promoter/regulator system, but high volumetric yields of GM-CSF and scFv-phOx (up to 1.7 and 2.3 g/liter, respectively) were achieved when the respective genes were fused to a translocation signal sequence. The choice of signal sequence, pelB, ompA, or synthetic signal sequence CSP, displayed a high and specific impact on the total expression levels for these two proteins. Data obtained by quantitative PCR confirmed relatively high in vivo transcript levels without using a fused signal sequence, suggesting that the signal sequences mainly stimulate translation. IFN-alpha2b expression remained poor even when fused to a signal sequence, and an alternative IFN-alpha2b coding sequence that was optimized for effective expression in Escherichia coli was therefore synthesized. The total expression level of this optimized gene remained low, while high-level production (0.6 g/liter) was achieved when the gene was fused to a signal sequence. Together, our results demonstrate a critical role of signal sequences for achieving industrial level expression of three human proteins in E. coli under the conditions tested, and this effect has to our knowledge not previously been systematically investigated.
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Affiliation(s)
- H Sletta
- SINTEF Materials and Chemistry, Department of Biotechnology, SINTEF, Sem Selands vei 2, 7465 Trondheim, Norway
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Tøndervik A, Torgersen HR, Botnmark HK, Strøm AR. Transposon mutations in the 5' end of glnD, the gene for a nitrogen regulatory sensor, that suppress the osmosensitive phenotype caused by otsBA lesions in Escherichia coli. J Bacteriol 2006; 188:4218-26. [PMID: 16740928 PMCID: PMC1482954 DOI: 10.1128/jb.00513-05] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [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: 11/20/2022] Open
Abstract
GlnD of Escherichia coli is a bifunctional signal-transducing enzyme (102.4 kDa) which uridylylates the allosteric regulatory protein PII and deuridylylates PII-UMP in response to growth with nitrogen excess or limitation, respectively. GlnD catalyzes these reactions in response to high or low levels of cytoplasmic glutamine, respectively, and indirectly directs the expression of nitrogen-regulated genes, e.g., the glnK-amtB operon. We report that chromosomal mini-Tn10 insertions situated after nucleotide number 997 or 1075 of glnD partially suppressed the osmosensitive phenotype of DeltaotsBA or otsA::Tn10 mutations (defective osmoregulatory trehalose synthesis). Strains carrying these glnD::mini-Tn10 mutations either completely repressed the expression of trp::(glnKp-lacZ) or induced this reporter system to nearly 60% of the wild-type glnD level in response to nitrogen availability, an essentially normal response. This was in contrast to the much-studied glnD99::Tn10 mutation, which carries its insertion in the 3' end of the gene, causes a complete repression of glnKp-lacZ expression under all growth conditions, and also confers leaky glutamine auxotrophy. When expressed from the Pm promoter in plasmid constructs, the present glnD mutations produced proteins with an apparent mass of 39 or 42 kDa. These proteins were deduced to comprise 344 or 370 N-terminal residues, respectively, harboring the known nucleotidyltransferase domain of GlnD, plus a common C-terminal addition of 12 residues encoded by IS10. They lacked three other domains of GlnD. Apparently, the transferase domain by itself enabled the cells to catalyze the uridylylation reaction and direct nitrogen-regulated gene expression. Our data indicate that there exists a link between osmotic stress and the nitrogen response.
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Affiliation(s)
- Anne Tøndervik
- The Norwegian University of Science and Technology, Department of Biotechnology, Trondheim N-7491, Norway
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Manzanera M, García de Castro A, Tøndervik A, Rayner-Brandes M, Strøm AR, Tunnacliffe A. Hydroxyectoine is superior to trehalose for anhydrobiotic engineering of Pseudomonas putida KT2440. Appl Environ Microbiol 2002; 68:4328-33. [PMID: 12200283 PMCID: PMC124095 DOI: 10.1128/aem.68.9.4328-4333.2002] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [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: 11/20/2022] Open
Abstract
Anhydrobiotic engineering aims to increase the level of desiccation tolerance in sensitive organisms to that observed in true anhydrobiotes. In addition to a suitable extracellular drying excipient, a key factor for anhydrobiotic engineering of gram-negative enterobacteria seems to be the generation of high intracellular concentrations of the nonreducing disaccharide trehalose, which can be achieved by osmotic induction. In the soil bacterium Pseudomonas putida KT2440, however, only limited amounts of trehalose are naturally accumulated in defined high-osmolarity medium, correlating with relatively poor survival of desiccated cultures. Based on the enterobacterial model, it was proposed that increasing intracellular trehalose concentration in P. putida KT2440 should improve survival. Using genetic engineering techniques, intracellular trehalose concentrations were obtained which were similar to or greater than those in enterobacteria, but this did not translate into improved desiccation tolerance. Therefore, at least for some populations of microorganisms, trehalose does not appear to provide full protection against desiccation damage, even when present at high concentrations both inside and outside the cell. For P. putida KT2440, it was shown that this was not due to a natural limit in desiccation tolerance since successful anhydrobiotic engineering was achieved by use of a different drying excipient, hydroxyectoine, with osmotically preconditioned bacteria for which 40 to 60% viability was maintained over extended periods (up to 42 days) in the dry state. Hydroxyectoine therefore has considerable potential for the improvement of desiccation tolerance in sensitive microorganisms, particularly for those recalcitrant to trehalose.
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Affiliation(s)
- M Manzanera
- Institute of Biotechnology, University of Cambridge, Cambridge CB2 1QT, United Kingdom
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Haugan K, Karunakaran P, Tøndervik A, Valla S. The host range of RK2 minimal replicon copy-up mutants is limited by species-specific differences in the maximum tolerable copy number. Plasmid 1995; 33:27-39. [PMID: 7753906 DOI: 10.1006/plas.1995.1004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [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: 01/27/2023]
Abstract
The minimal replicon of the broad-host-range plasmid RK2 consists of a gene, trfA (trans-acting replication), encoding a protein required for initiation of plasmid replication. The TrfA protein binds to iterons in the cis-acting origin of vegetative replication (oriV), but the exact mechanism by which TrfA-mediated replication initiation takes place is not known. We report here the isolation and characterization of five mini RK2 trfA mutant plasmids with an elevated plasmid copy number, four in Pseudomonas aeruginosa and one in Azotobacter vinelandii. The mutations are localized between or downstream of previously reported Escherichia coli copy-up mutations in trfA, and one of the mutations has been described earlier as an independent copy-up isolate in E. coli. The five mutant plasmids were all moderately copy up in both E. coli and their host of origin, in spite of the use of isolation procedures which were expected to select efficiently in favor of plasmid mutants specifying high copy numbers. In contrast, previously described high copy-up mutants isolated in E. coli could not be established in P. aeruginosa and A. vinelandii. These high copy-up mutants were shown to induce cell killing in E. coli under conditions where the plasmid copy number was increased as a physiological response to reduced growth rate. We propose that the reason for this killing effect is that the copy number under these conditions exceeds an upper tolerance level specific for E. coli. By assuming that the corresponding tolerance level is lower in P. aeruginosa and A. vinelandii than in E. coli, and that the mechanism of copy number regulation is similar, the model can explain the phenotypes of all tested copy up mutants in these two hosts. Analogous studies were also performed in Salmonella typhimurium and Acetobacter xylinum. The data obtained in these studies indicate that the above model is probably generally true for gram-negative bacteria, and the results also indicate that the maximum tolerable copy number is surprisingly low in some hosts.
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Affiliation(s)
- K Haugan
- UNIGEN Center for Molecular Biology, University of Trondheim, Norway
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