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    • "Galectins belong to the family of -galactoside-binding proteins (Barondes et al., 1994) of which 15 galectin members have been characterized to date (Cooper, 2002; Hirabayashi and Kasai, 1993). Generally, galectins have a conserved region of 130–150 amino acid residues that form a carbohydrate recognition domain (CRD) and contain a unique WG-E motif that is specific for saccharide binding (Cooper and Barondes, 1999). "
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    ABSTRACT: Galectins belong to the family of galactoside-binding proteins and play a major role in the immune and inflammatory responses of vertebrates and invertebrates. The galectin family is divided into three sub-types based on molecular structure; prototypes, chimera types, and tandem-repeated types. We isolated and characterized the cDNA of galectin-8 (OnGal-8) in Nile tilapia (Oreochromis niloticus). OnGal-8 consisted of a 966 bp open reading frame (ORF) that encoded a 321 amino acid protein (43.47 kDa). Homology and phylogenetic tree analysis suggested the protein was clustered with galectin-8s from other animal species and shared at least 56.8% identity with salmon galectin-8. Structurally, the amino acid sequence included two distinct N-and C-terminus carbohydrate recognition domains (CRDs) of 135 and 133 amino acids, respectively, that were connected by a 39 amino acid polypeptide linker. The N-and C-CRDs contained two conserved WG-E-I and WG-E-T motifs, suggesting they have an important role in mediating the specific interactions between OnGal-8 and saccharide moieties such as-galactoside. The structure of OnGal-8 was characterized by a twofold symmetric pattern of 10-and 12-stranded antiparallel ß-sheets of both N-and C-CRDs, and the peptide linker presumably formed a random coil similar to the characteristic tandem-repeat type galectin. The expression of OnGal-8 in healthy fish was highest in the skin, intestine, and brain. Experimental challenge of Nile tilapia with S. agalactiae resulted in significant up-regulation of OnGal-8in the spleen after 5 d. Our results suggest that OnGal-8 is involved in the immune response to bacterial infection.
    Molecular Immunology 10/2015; DOI:10.1016/j.molimm.2015.09.012 · 2.97 Impact Factor
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    • "Despite extensive research, only very few endogenous ligands for TLR4 have been described so far (Chen and Nuñ ez, 2010). Galectins represent a protein family with at least 15 members that have significant sequence similarity in their carbohydraterecognition domain (CRD) and bind to b-galactosides with varying affinities and specificities (Barondes et al., 1994; Leffler et al., 2004). Galectins are classified into three subgroups (1) proto, (2) chimera, and (3) tandem repeat based on their molecular architecture . "
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    ABSTRACT: Graphical Abstract Highlights d Gal3 acts as an endogenous TLR4 ligand with a Kd value around 1 mM d Gal3 can initiate a TLR4-dependent inflammatory response in microglia d Gal3 is required for complete activation of TLR4 upon LPS treatment d Gal3-TLR4 interaction is confirmed in vivo and in stroke patients In Brief In this publication, Burguillos et al. demonstrate how galectin-3 (Gal3) released from reactive microglia cells can activate other surrounding immune cells in a paracrine manner by binding to and activating Toll-like receptor 4 (TLR4). This finding could explain the propagation of the inflammatory response once the initial stimulus is gone.
    Cell Reports 04/2015; 10(9):1626-1638. DOI:10.1016/j.celrep.2015.02.012 · 8.36 Impact Factor
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    • "Classifications and the detailed structural and functional information of lectins are available in the widely distributed databases and literatures (Sharon and Lis, 2004; Chandra et al., 2006; Damodaran et al., 2008; Pérez et al., 2014). Galectins (previously termed S-type lectins) are β-galactoside binding proteins which have at least one carbohydrate recognition domain and certain conserved sequence elements (Barondes et al., 1994a, 1994b; Cummings and Liu, 2009). Galectins have the ability to serve as potent antitumors and cancer biomarkers as they induce tumor cell apoptosis (Kim et al., 1993; Hengartner, 2000; Rabinovich, 2005; Yang et al., 2005; Yang et al., 2009; Balan et al., 2010). "
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    ABSTRACT: Galectins are β-galactoside binding proteins which have the ability to serve as potent antitumor, cancer biomarker, and induce tumor cell apoptosis. Agrocybe cylindracea galectin (ACG) is a fungal galectin which specifically recognizes α(2,3)-linked sialyllactose at the cell surface that plays extensive roles in the biological recognition processes. To investigate the change in glycan-binding specificity upon mutations, single point and double point site-directed in silico mutations are performed at the binding pocket of ACG. Molecular dynamics (MD) simulation studies are carried out for the wild-type (ACG) and single point (ACG1) and double point (ACG2) mutated ACGs to investigate the dynamics of substituted mutants and their interactions with the receptor sialyllactose. Plausible binding modes are proposed for galectin-sialylglycan complexes based on the analysis of hydrogen bonding interactions, total pair-wise interaction energy between the interacting binding site residues and sialyllactose and binding free energy of the complexes using molecular mechanics-Poisson-Boltzmann surface area. Our result shows that high contribution to the binding in different modes is due to the direct and water-mediated hydrogen bonds. The binding specificity of double point mutant Y59R/N140Q of ACG2 is found to be high, and it has 26 direct and water-mediated hydrogen bonds with a relatively low-binding free energy of -47.52 ± 5.2 kcal/mol. We also observe that the substituted mutant Arg59 is crucial for glycan-binding and for the preference of α(2,3)-linked sialyllactose at the binding pocket of ACG2 galectin. When compared with the wild-type and single point mutant, the double point mutant exhibits enhanced affinity towards α(2,3)-linked sialyllactose, which can be effectively used as a model for biological cell marker in cancer therapeutics. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Molecular Recognition 03/2015; 28(9). DOI:10.1002/jmr.2468 · 2.15 Impact Factor
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