26 April, 2018
A Workshop of the GLICOENZ Consorptium was held on April 25th 2018 at the Faculty of Sciences of the Autonomous University of Madrid. The students of the four laboratories involved in GLICOENZ presented their main results. These presentations served as a basis for planning new experiments and initiating new sinergies.
24 April, 2018
Chitinase Chit42 from Trichoderma harzianum hydrolyses chitin oligomers with a minimal of three N-acetyl-D-glucosamine (GlcNAc) units. Chit42 was expressed in Pichia pastoris using fed-batch fermentation to about 3 g/L. In addition to hydrolyse colloidal chitin, this enzyme released reducing sugars from commercial chitosan of different sizes and acetylation degrees. Production of partially acetylated chitooligosaccharides was confirmed in reaction mixtures using HPAEC-PAD chromatography and mass spectrometry. Crystals from Chit42 were grown and the 3D structure determined at 1.8 Å resolution, showing the expected folding described for other GH18 chitinases, and a characteristic groove shaped substrate-binding site, able to accommodate at least six sugar units. Detailed structural analysis allows depicting the features of the Chit42 specificity, and explains the chemical nature of the partially acetylated molecules obtained from analysed substrates.
Reference: “Use of chitin and chitosan to produce new chitooligosaccharides by chitinase Chit42: enzymatic activity and structural basis of protein specificity”. P.E. Kidibule, P. Santos-Moriano, E. Jiménez-Ortega, M. Ramírez-Escudero, M.C. Limón, M. Remacha, F.J. Plou, J. Sanz-Aparicio, M. Fernández-Lobato. Microbial Cell Factories 17:47 (2018). doi:10.1186/s12934-018-0895-x
08 January, 2018
Reference: “Enzymatic production of fully deacetylated chitooligosaccharides and their neuroprotective and anti-inflammatory properties”. P. Santos-Moriano, L. Fernandez-Arrojo, M. Mengibar, E. Belmonte-Reche, P. Peñalver, F.N. Acosta, P. Kidibule, A.O. Ballesteros, J.C. Morales, M. Fernandez-Lobato and F.J. Plou. Biocatalysis and Biotransformation (2017), doi: 10.1080/10242422.2017.1295231
16 November, 2017
The α-glucosidase gene of Aspergillus niger was expressed in Saccharomyces cerevisiae under control of a galactose-inducible promoter. Recombinant yeast cells expressing the aglA gene produced extracellular α-glucosidase activity. With maltose as the substrate, panose is the main transglycosylation product after 8 h of incubation, whereas isomaltose is predominant after 24 h. Isomaltose also becomes predominant at shorter times if a mixture of maltose and glucose is used instead of maltose. To facilitate IMO production, we have designed a procedure by which yeast cells can be used directly as the catalytic agent. For this purpose, we expressed in S. cerevisiae gene constructs in which the aglA gene is fused to glycosylphosphatidylinositol anchor sequences, from the yeast SED1 gene, that determine the covalent binding of the hybrid protein to the cell membrane. The resulting hybrid enzymes were stably attached to the cell surface. The cells from cultures of recombinant yeast strains expressing aglA-SED1 constructions can be used to produce IMOs in successive batches.
Reference: M. Casa-Villegas, J. Marín-Navarro, J. Polaina. "Synthesis of isomaltooligosaccharides by Saccharomyces cerevisiae cells expressing Aspergillus niger alpha-glucosidases". ACS Omega 2, 11, 8062-8068 (2017). doi:10.1021/acsomega.7b01189
22 August, 2017
21 April, 2016
Francisco Plou has just published the book "What we know about ...The Enzymes", a disclosure book jointly edited by CSIC and Catarata Publishers. The aim of this book is bringing the world of enzymes to readers, and show them the importance of these biological catalysts in our health and in many aspects of our daily life (food, drugs, fuels, polymers, etc.). It includes many aspects related to the enzymes acting on carbohydrates.
18 April, 2016
Reference: D. Talens-Perales, J. Polaina, and J. Marín-Navarro. "Structural Dissection of the Active Site of Thermotoga maritima β‑Galactosidase Identifies Key Residues for Transglycosylating Activity". J. Agric. Food Chem. 2016, 64, 2917−2924. DOI: 10.1021/acs.jafc.6b00222
02 February, 2016
Ramírez-Escudero, M., Gimeno-Pérez, M., González, B., Linde, D., Merzdo, Z. Fernández-Lobato, M., Sanz-Aparicio, J.,"Structural analysis of β-fructofuranosidase from Xanthophyllomyces dendrorhous reveals unique features and the crucial role of N-glycosylation in oligomerization and activity". J. Biol. Chem. (2016). doi:10.1074/jbc.M115.708495
14 January, 2016
Link to the article
02 December, 2015
"Molecular characterization and heterologous expression of a Xanthophyllomyces dendrorhous α-glucosidase with potential for prebiotics production". Patricia Gutiérrez-Alonso, María Gimeno-Pérez, Mercedes Ramírez-Escudero, Francisco J. Plou, Julia Sanz-Aparicio, María Fernández-Lobato. Applied Microbiology and Biotechnolog,, first online: 28 November 2015. DOI: 10.1007/s00253-015-7171