Ecosystem Model Proposal in the Tourism Sector to Enhance Sustainable Competitiveness

[EN] Service companies in developed countries represent 70-80% of the Gross Domestic Product (GDP). In Spain, within the service sector, tourism is the main contributor and is growing annually. This is obviously an opportunity for the country due to its benefits and economic e¿ects but at the same time a well-structured, sustainable and competitive model for its continued development is needed in order to adopt best practices and reference innovative models from other sectors. A qualitative approach using Case Study, Grounded Theory and Delphi Method has been conducted to study the tourism sector in the city of Gandia, Valencia (Spain). Results show that a tourist destination with its different components and stakeholders involved in its value chain can be interpreted as an ecosystem and so reference ecosystem models could be adopted to boost the development of a region. Considering the results obtained, this study can contribute to the development of a tourist destination in a sustainable and innovative way.Morant-Martínez, O.; Santandreu Mascarell, C.; Canós-Darós, L.; Millet Roig, J. (2019). Ecosystem Model Proposal in the Tourism Sector to Enhance Sustainable Competitiveness. Sustainability. 11(23):1-15. https://doi.org/10.3390/su11236652S115112

From 1,4-Disaccharide to 1,3-Glycosyl Carbasugar : Synthesis of a Bespoke Inhibitor of Family GH99 Endo-α-mannosidase

Understanding the enzyme reaction mechanism can lead to the design of enzyme inhibitors. A Claisen rearrangement was used to allow conversion of an α-1,4-disaccharide into an α-1,3-linked glycosyl carbasugar to target the endo-α-mannosidase from the GH99 glycosidase family, which, unusually, is believed to act through a 1,2-anhydrosugar "epoxide" intermediate. Using NMR and X-ray crystallography, it is shown that glucosyl carbasugar α-aziridines can act as reasonably potent endo-α-mannosidase inhibitors, likely by virtue of their shape mimicry and the interactions of the aziridine nitrogen with the conserved catalytic acid/base of the enzyme active site

Valencia Startup Ecosystem: una aproximación al ecosistema emprendedor de Valencia y sus características frente a los rankings internacionales

Morant-Martínez, O.; Santandreu Mascarell, C.; Canós-Darós, L.; Millet Roig, J. (2017). Valencia Startup Ecosystem: una aproximación al ecosistema emprendedor de Valencia y sus características frente a los rankings internacionales. Economía Industrial. 404:63-70. http://hdl.handle.net/10251/101443S637040

Macromolecular Crowding Fails To Fold a Globular Protein in Cells

Proteins perform their function in cells where macromolecular solutes reach concentrations of >300 g/L and occupy >30% of the volume. The volume excluded by these macromolecules will stabilize globular proteins because the native state occupies less space than the denatured state. Theory predicts that crowding can increase the ratio of folded to unfolded protein by a factor of 100, amounting to 3 kcal/mol of stabilization at room temperature. We tested the idea that volume exclusion dominates the crowding effect in cells with a variant of protein L, a 7-kDa globular protein with seven lysine residues replaced by glutamic acids. Eighty-four percent of the variant molecules populate the denatured state in dilute buffer at room temperature, compared to 0.1% for the wild-type protein. We then used in-cell nuclear magnetic resonance spectroscopy to show that the cytoplasm of Escherichia coli does not overcome even this modest (~1 kcal/mol) free energy deficit. The data are consistent with the idea that non-specific interactions between cytoplasmic components can overcome the excluded volume effect. Evidence for these interactions is provided by the observation that adding simple salts folds the variant in dilute solution, but increasing the salt concentration inside E. coli does not fold the protein. Our data are consistent with other studies of protein stability in cells, and suggest that stabilizing excluded volume effects, which must be present under crowded conditions, can be ameliorated by non-specific interactions between cytoplasmic components

Unravelling the Time Scale of Conformational Plasticity and Allostery in Glycan Recognition by Human Galectin-1

The interaction of human galectin-1 with a variety of oligosaccharides, from di-(N-acetyllactosamine) to tetra-saccharides (blood B type-II antigen) has been scrutinized by using a combined approach of different NMR experiments, molecular dynamics (MD) simulations, and isothermal titration calorimetry. Ligand- and receptor-based NMR experiments assisted by computational methods allowed proposing three-dimensional structures for the different complexes, which explained the lack of enthalpy gain when increasing the chemical complexity of the glycan. Interestingly, and independently of the glycan ligand, the entropy term does not oppose the binding event, a rather unusual feature for protein-sugar interactions. CLEANEX-PM and relaxation dispersion experiments revealed that sugar binding affected residues far from the binding site and described significant changes in the dynamics of the protein. In particular, motions in the microsecond-millisecond timescale in residues at the protein dimer interface were identified in the presence of high affinity ligands. The dynamic process was further explored by extensive MD simulations, which provided additional support for the existence of allostery in glycan recognition by human galectin-1.This research was supported by the European Research Council (ERC-2017-AdG, project 788143-RECGLYCANMR to J.J.-B.), Agencia Estatal Investigacion of Spain (AEI; grant RTI2018-094751-B-C21 to J.J.-B., RTI2018-099592-B-C22 to G.J.O, RTI2018-101269-B-I00 to O. M., and Ramon y Cajal Contract to A. A.) and the Severo Ochoa Excellence Accreditation (SEV-2016-0644 to J.J.-B.). We also thank Instituto de Salud Carlos III of Spain, ISCIII (grant PRB3 IPT17/0019 to A. G.) and the Mizutani Foundation for Glycoscience (grant 200077 to G.J.O.)

Disulfide driven folding for a conditionally disordered protein

Altres ajuts: ICREA, ICREA-Academia 2015 to S.V.Conditionally disordered proteins are either ordered or disordered depending on the environmental context. The substrates of the mitochondrial intermembrane space (IMS) oxidoreductase Mia40 are synthesized on cytosolic ribosomes and diffuse as intrinsically disordered proteins to the IMS, where they fold into their functional conformations; behaving thus as conditionally disordered proteins. It is not clear how the sequences of these polypeptides encode at the same time for their ability to adopt a folded structure and to remain unfolded. Here we characterize the disorder-to-order transition of a Mia40 substrate, the human small copper chaperone Cox17. Using an integrated real-time approach, including chromatography, fluorescence, CD, FTIR, SAXS, NMR, and MS analysis, we demonstrate that in this mitochondrial protein, the conformational switch between disordered and folded states is controlled by the formation of a single disulfide bond, both in the presence and in the absence of Mia40. We provide molecular details on how the folding of a conditionally disordered protein is tightly regulated in time and space, in such a way that the same sequence is competent for protein translocation and activity

Contribution of shape and charge to the inhibition of a family GH99 endo-α-1,2-mannanase

[Image: see text] Inhibitor design incorporating features of the reaction coordinate and transition-state structure has emerged as a powerful approach for the development of enzyme inhibitors. Such inhibitors find use as mechanistic probes, chemical biology tools, and therapeutics. Endo-α-1,2-mannosidases and endo-α-1,2-mannanases, members of glycoside hydrolase family 99 (GH99), are interesting targets for inhibitor development as they play key roles in N-glycan maturation and microbiotal yeast mannan degradation, respectively. These enzymes are proposed to act via a 1,2-anhydrosugar “epoxide” mechanism that proceeds through an unusual conformational itinerary. Here, we explore how shape and charge contribute to binding of diverse inhibitors of these enzymes. We report the synthesis of neutral dideoxy, glucal and cyclohexenyl disaccharide inhibitors, their binding to GH99 endo-α-1,2-mannanases, and their structural analysis by X-ray crystallography. Quantum mechanical calculations of the free energy landscapes reveal how the neutral inhibitors provide shape but not charge mimicry of the proposed intermediate and transition state structures. Building upon the knowledge of shape and charge contributions to inhibition of family GH99 enzymes, we design and synthesize α-Man-1,3-noeuromycin, which is revealed to be the most potent inhibitor (K(D) 13 nM for Bacteroides xylanisolvens GH99 enzyme) of these enzymes yet reported. This work reveals how shape and charge mimicry of transition state features can enable the rational design of potent inhibitors

Redox regulation of KV7 channels through EF3 hand of calmodulin

Neuronal KV7 channels, important regulators of cell excitability, are among the most sensitive proteins to reactive oxygen species. The S2S3 linker of the voltage sensor was reported as a site-mediating redox modulation of the channels. Recent structural insights reveal potential interactions between this linker and the Ca2+-binding loop of the third EF-hand of calmodulin (CaM), which embraces an antiparallel fork formed by the C-terminal helices A and B, constituting the calcium responsive domain (CRD). We found that precluding Ca2+ binding to the EF3 hand, but not to EF1, EF2, or EF4 hands, abolishes oxidation-induced enhancement of KV7.4 currents. Monitoring FRET (Fluorescence Resonance Energy Transfer) between helices A and B using purified CRDs tagged with fluorescent proteins, we observed that S2S3 peptides cause a reversal of the signal in the presence of Ca2+ but have no effect in the absence of this cation or if the peptide is oxidized. The capacity of loading EF3 with Ca2+ is essential for this reversal of the FRET signal, whereas the consequences of obliterating Ca2+ binding to EF1, EF2, or EF4 are negligible. Furthermore, we show that EF3 is critical for translating Ca2+ signals to reorient the AB fork. Our data are consistent with the proposal that oxidation of cysteine residues in the S2S3 loop relieves KV7 channels from a constitutive inhibition imposed by interactions between the EF3 hand of CaM which is crucial for this signaling.Ministerio de Ciencia e Innovacion PID2021-128286NB-100Wellcome Trust 212302/Z/18/ZMedical Research Centre MR/P015727/1Eusko Jaurlaritza IT1707-22 Ekonomiaren Garapen eta Lehiakortasun Saila, Eusko Jaurlaritza BG2019Ministerio de Ciencia e Innovacion RTI2018-097839-B-100Ministerio de Ciencia e Innovacion RTI2018-101269-B-I00Eusko Jaurlaritza IT1165-19 Ekonomiaren Garapen eta Lehiakortasun Saila,Eusko Jaurlaritza KK-2020/00110Eusko Jaurlaritza PRE_2018-2_0082Eusko Jaurlaritza POS_2021_1_0017Eusko Jaurlaritza PRE_2018-2_012

Fluorinated Carbohydrates as Lectin Ligands: Simultaneous Screening of a Monosaccharide Library and Chemical Mapping by F-19 NMR Spectroscopy

Molecular recognition of carbohydrates is a key step in essential biological processes. Carbohydrate receptors can distinguish monosaccharides even if they only differ in a single aspect of the orientation of the hydroxyl groups or harbor subtle chemical modifications. Hydroxyl-by-fluorine substitution has proven its merits for chemically mapping the importance of hydroxyl groups in carbohydrate-receptor interactions. F-19 NMR spectroscopy could thus be adapted to allow contact mapping together with screening in compound mixtures. Using a library of fluorinated glucose (Glc), mannose (Man), and galactose (Gal) derived by systematically exchanging every hydroxyl group by a fluorine atom, we developed a strategy combining chemical mapping and F-19 NMR T-2 filtering-based screening. By testing this strategy on the proof-of-principle level with a library of 13 fluorinated monosaccharides to a set of three carbohydrate receptors of diverse origin, i.e. the human macrophage galactose-type lectin, a plant lectin, Pisum sativum agglutinin, and the bacterial Gal-/Glc-binding protein from Escherichia coli, it became possible to simultaneously define their monosaccharide selectivity and identify the essential hydroxyls for interactionAgencia Estatal de Investigacion (Spain) Grants CTQ2015-64597-C2-1-P and 2-P, RTI2018-094751-B-C21 and C22, Severo Ochoa Excellence Accreditation (SEV-2016-0644) European Research Council (RECGLYCANMR, Advanced Grant No. 788143), and CIBERES, an initiative from the Spanish Institute of Health Carlos III. Science Foundation Ireland, SFI Award 13/IA/195

Side chain to main chain hydrogen bonds stabilize a polyglutamine helix in a transcription factor

Polyglutamine (polyQ) tracts are low-complexity regions and their expansion is linked to certain neurodegenerative diseases. Here the authors combine experimental and computational approaches to find that the length of the androgen receptor polyQ tract correlates with its helicity and show that the polyQ helical structure is stabilized by hydrogen bonds between the Gln side chains and main chain carbonyl groups