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  • 1.
    Guerriero, Gea
    et al.
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Martin, Nathalie
    Golovko, Anna
    Sundstrom, Jens F.
    Rask, Lars
    Ezcurra, Inés
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    The RY/Sph element mediates transcriptional repression of maturation genes from late maturation to early seedling growth2009In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 184, no 3, p. 552-565Article in journal (Refereed)
    Abstract [en]

    P>In orthodox seeds, the transcriptional activator ABI3 regulates two major stages in embryo maturation: a mid-maturation (MAT) stage leading to accumulation of storage compounds, and a late maturation (LEA) stage leading to quiescence and desiccation tolerance. Our aim was to elucidate mechanisms for transcriptional shutdown of MAT genes during late maturation, to better understand phase transition between MAT and LEA stages. Using transgenic and transient approaches in Nicotiana, we examined activities of two ABI3-dependent reporter genes driven by multimeric RY and abscisic acid response elements (ABREs) from a Brassica napus napin gene, termed RY and ABRE, where the RY reporter requires ABI3 DNA binding. Expression of RY peaks during mid-maturation and drops during late maturation, mimicking the MAT gene program, and in Arabidopsis thaliana RY elements are over-represented in MAT, but not in LEA, genes. The ABI3 transactivation of RY is inhibited by staurosporine, by a PP2C phosphatase, and by a repressor of maturation genes, VAL1/HSI2. The RY element mediates repression of MAT genes, and we propose that transcriptional shutdown of the MAT program during late maturation involves inhibition of ABI3 DNA binding by dephosphorylation. Later, during seedling growth, VAL1/HSI2 family repressors silence MAT genes by binding RY elements. New Phytologist (2009)doi: 10.1111/j.1469-8137.2009.02977.x.

  • 2.
    Gullfot, Fredrika
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    On the engineering of proteins: methods and applications for carbohydrate-active enzymes2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents the application of different protein engineering methods on enzymes and non-catalytic proteins that act upon xyloglucans. Xyloglucans are polysaccharides found as storage polymers in seeds and tubers, and as cross-linking glucans in the cell wall of plants. Their structure is complex with intricate branching patterns, which contribute to the physical properties of the polysaccharide including its binding to and interaction with other glucans such as cellulose.

    One important group of xyloglucan-active enzymes is encoded by the GH16 XTH gene family in plants, including xyloglucan endo-transglycosylases (XET) and xyloglucan endo-hydrolases (XEH). The molecular determinants behind the different catalytic routes of these homologous enzymes are still not fully understood. By combining structural data and molecular dynamics (MD) simulations, interesting facts were revealed about enzyme-substrate interaction. Furthermore, a pilot study was performed using structure-guided recombination to generate a restricted library of XET/XEH chimeras.

    Glycosynthases are hydrolytically inactive mutant glycoside hydrolases (GH) that catalyse the formation of glycosidic linkages between glycosyl fluoride donors and glycoside acceptors. Different enzymes with xyloglucan hydrolase activity were engineered into glycosynthases, and characterised as tools for the synthesis of well-defined homogenous xyloglucan oligo- and polysaccharides with regular substitution patterns.

    Carbohydrate-binding modules (CBM) are non-catalytic protein domains that bind to polysaccharidic substrates. An important technical application involves their use as molecular probes to detect and localise specific carbohydrates in vivo. The three-dimensional structure of an evolved xyloglucan binding module (XGBM) was solved by X-ray diffraction. Affinity-guided directed evolution of this first generation XGBM resulted in highly specific probes that were used to localise non-fucosylated xyloglucans in plant tissue sections.

  • 3.
    Gullfot, Fredrika
    et al.
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Teeri, Tuula
    KTH, School of Biotechnology (BIO), Glycoscience.
    Brumer, Harry
    KTH, School of Biotechnology (BIO), Glycoscience.
    Design of GH16 XET/XEH chimeric enzymes with SCHEMA: ManuscriptManuscript (preprint) (Other academic)
    Abstract [en]

    This manuscript contains experimental data obtained during a pilot study for the application of the SCHEMA method for structure-guided recombination on PttXET16-34 and TmNXG1, a model system for the evolution of different catalytic routes of GH16 XETs and XEHs.

    A restricted library of PttXET16-34/TmNXG1 chimeras with high diversity and low calculated SCHEMA disruption was generated based on crossover points identified by the RASPP algorithm. Analysis of the library revealed a bias among certain regions to remain intact and recalcitrant to recombination, in particular the upper and lower β-sheet structures forming the part of the protein that binds the donor substrate. In contrast, sequence diversity was preferentially introduced at the N-terminus, the major part of the acceptor side of the protein, and most of the C-terminal extension characteristic to XET/XEH in the GH16 family. Finally, in order to test the predictive capacity of SCHEMA, six chimeras with low calculated disruption were chosen for subsequent cloning and expression in Pichia pastoris.

  • 4.
    Jonsson Rudsander, Ulla
    et al.
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Sandstrom, Corine
    Piens, Kathleen
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Master, Emma
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Wilson, David B.
    Brumer, Harry
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Biotechnology (BIO), Glycoscience.
    Kenne, Lennart
    Teeri, Tuula T.
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Biotechnology (BIO), Glycoscience.
    Comparative NMR analysis of cellooligosaccharide hydrolysis by GH9 bacterial and plant endo-1,4-ss-glucanases2008In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 47, no 18, p. 5235-5241Article in journal (Refereed)
    Abstract [en]

    H-1 NMR spectroscopy has been used to analyze the product profiles arising from the hydrolysis of cellooligosaccharides by family GH9 cellulases. The product profiles obtained with the wild type and several active site mutants of a bacterial processive endoglucanase, Tf Cel9A, were compared with those obtained by a randomly acting plant endoglucanase, PttCe19A. PttCe19A is an orthologue of the Arabidopsis endocellulase, Korrigan, which is required for efficient cellulose biosynthesis. As expected, poplar PttCe19A was shown to catalyze the degradation of cellooligosaccharides by inversion of the configuration of the anomeric carbon. The product analyses showed that the number of interactions between the glucose units of the substrate and the aromatic residues in the enzyme active sites determines the point of cleavage in both enzymes.

  • 5.
    Kochumalayil, Joby
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Sehaqui, Houssine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Tamarind seed xyloglucan: a promising biopolymer matrix for bioinspired nanocomposite materials2010Conference paper (Other academic)
  • 6.
    Kochumalayil, Joby
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Sehaqui, Houssine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Zhou, Qi
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Xyloglucan films2009Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention pertains to films comprising xyloglucan, processes for preparing films comprising xyloglucan, as well as various uses of said films as for instance packaging material. Specifically, the present invention relates to xyloglucan films having advantageous properties relating to inter alia tensile strength, elastic modulus, and strain-to-failure.

  • 7.
    Kochumalayil, Joby
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Nanostructured high-performance biocomposites based on Tamarind seed polysaccharide2011Conference paper (Other academic)
  • 8.
    Kochumalayil, Joby
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Zhou, Qi
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Nanostructured high-performance biocomposites based on Tamarind seed xyloglucan2011Conference paper (Other academic)
  • 9.
    Rajangam, Alex S.
    et al.
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Kumar, Manoj
    Aspeborg, Henrik
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Guerriero, Gea
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Arvestad, Lars
    KTH, School of Computer Science and Communication (CSC), Computational Biology, CB.
    Pansri, Podjamas
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Brown, Christian J. L.
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Hober, Sophia
    KTH, School of Biotechnology (BIO), Proteomics (closed 20130101).
    Blomqvist, Kristina
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Divne, Christina
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Ezcurra, Inés
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Mellerowicz, Ewa
    Sundberg, Bjorn
    Bulone, Vincent
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    Teeri, Tuula T.
    KTH, School of Biotechnology (BIO), Glycoscience. KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime.
    MAP20, a Microtubule-Associated Protein in the Secondary Cell Walls of Hybrid Aspen, Is a Target of the Cellulose Synthesis Inhibitor 2,6-Dichlorobenzonitrile2008In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 148, no 3, p. 1283-1294Article in journal (Refereed)
    Abstract [en]

    We have identified a gene, denoted PttMAP20, which is strongly up-regulated during secondary cell wall synthesis and tightly coregulated with the secondary wall-associated CESA genes in hybrid aspen (Populus tremula x tremuloides). Immunolocalization studies with affinity-purified antibodies specific for PttMAP20 revealed that the protein is found in all cell types in developing xylem and that it is most abundant in cells forming secondary cell walls. This PttMAP20 protein sequence contains a highly conserved TPX2 domain first identified in a microtubule-associated protein (MAP) in Xenopus laevis. Overexpression of PttMAP20 in Arabidopsis (Arabidopsis thaliana) leads to helical twisting of epidermal cells, frequently associated with MAPs. In addition, a PttMAP20-yellow fluorescent protein fusion protein expressed in tobacco (Nicotiana tabacum) leaves localizes to microtubules in leaf epidermal pavement cells. Recombinant PttMAP20 expressed in Escherichia coli also binds specifically to in vitro-assembled, taxol-stabilized bovine microtubules. Finally, the herbicide 2,6-dichlorobenzonitrile, which inhibits cellulose synthesis in plants, was found to bind specifically to PttMAP20. Together with the known function of cortical microtubules in orienting cellulose microfibrils, these observations suggest that PttMAP20 has a role in cellulose biosynthesis.

  • 10.
    Rajangam, Alex Selvanayagam
    KTH, School of Biotechnology (BIO), Centres, Swedish Center for Biomimetic Fiber Engineering, BioMime. KTH, School of Biotechnology (BIO).
    Discovery and Characterization of a Novel Microtubule Associated Protein Involved in Cellulose Biosynthesis2008Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Cell walls are a distinct feature of plants and their chemical constituents, cellulose, hemicelluloses and lignin, are economically valuable. Plant fibres rich in cellulose, which mainly resides in their cell wall, are traditionally used in making paper and textiles. The changing global economic situation and environmental concerns have imparted necessity for renewable, but at the same time value added cellulosic materials. The Department of Wood Biotechnology, KTH together with its collaborators, have established EST libraries and performed transcript profiling during wood development in poplar, a tree considered as a model for wood development. The majority of the genes upregulated during cellulose biosynthesis encode proteins with known or predictable functions, such as carbohydrate active enzymes (CAzymes). However, some of them encode proteins with unknown functions. Characterization of these genes will potentially give additional opportunities to modify fibre properties. This thesis describes the discovery and characterization of a highly upregulated gene with a previously unknown function in poplar xylem, here denoted PttMAP20. Following its early discovery by mRNA profiling, the characterization was initiated with a thorough bioinformatic analysis, and the knowledge obtained was used to devise techniques for further functional analysis. Specific antibodies were raised, affinity purified and characterized. The antibodies were used as a tool for screening recombinant expression in E. coli and for the cellular localization of the protein in plant tissues, visualized with confocal and transmission electron microscopy. A purification protocol was developed for the expressed protein, followed by biochemical characterization. Appropriate model systems were used in both in vivo and in vitro studies. Fluorescently labelled protein transiently expressed in tobacco leaves was used for localization studies and the same system was used to characterize the molecular properties of the protein. Phenotypes arising from overexpressing the PttMAP20 gene were traced in the model plant Arabidopsis. All the results obtained so far indicate that PttMAP20 is a novel microtubule associated protein that binds to a cellulose biosynthesis inhibitor, DCB (2,6-dichlorobenzonitrile) and is required during cellulose biosynthesis in secondary cell walls.

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