Phylogeny and Properties of a Novel Lectin Family with β-Trefoil Folding in Mussels (original) (raw)
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Scientific Reports, 2016
MytiLec is a lectin, isolated from bivalves, with cytotoxic activity against cancer cell lines that express globotriaosyl ceramide, Galα(1,4)Galβ(1,4)Glcα1-Cer, on the cell surface. Functional analysis shows that the protein binds to the disaccharide melibiose, Galα(1,6)Glc and the trisaccharide globotriose, Galα(1,4)Galβ(1,4)Glc. Recombinant MytiLec expressed in bacteria showed the same haemagglutinating and cytotoxic activity against Burkitt’s lymphoma (Raji) cells as the native form. The crystal structure has been determined to atomic resolution, in the presence and absence of ligands, showing the protein to be a member of the β-trefoil family, but with a mode of ligand binding unique to a small group of related trefoil lectins. Each of the three pseudo-equivalent binding sites within the monomer shows ligand binding and the protein forms a tight dimer in solution. An engineered monomer mutant lost all cytotoxic activity against Raji cells, but retained some haemagglutination act...
Methods in molecular biology, 2020
In the 2010s, a novel lectin family with β-trefoil folding has been identified in marine mussels from the family Mytilidae (phylum Mollusca). "MytiLec-1," the lectin described in this chapter, was the first member of this family to be isolated and characterized from the Mediterranean mussel Mytilus galloprovincialis, a commercially and ecologically important species, spread in marine coastal areas worldwide. MytiLec-1 bound to the sugar moiety of globotriose (Gb3: Galα1-4Galβ1-4Glc), an α-galactoside, leading to apoptosis of Gb3-expressing Burkitt's lymphoma cells. Although the primary structure of MytiLec-1 was quite unusual, its three-dimensional structure was arranged as a β-trefoil fold, which is the typical architecture of "Ricin B chain (or R)-type" lectins, which are found in a broad range of organisms. To date, MytiLec-1-like lectins have been exclusively found in a few species of the mollusk family Mytilidae (M. galloprovincialis, M. trossulus, M. ca...
Activity Dependence of a Novel Lectin Family on Structure and Carbohydrate-Binding Properties
Molecules
A GalNAc/Gal-specific lectins named CGL and MTL were isolated and characterized from the edible mussels Crenomytilus grayanus and Mytilus trossulus. Amino acid sequence analysis of these lectins showed that they, together with another lectin MytiLec-1, formed a novel lectin family, adopting β-trefoil fold. In this mini review we discuss the structure, oligomerization, and carbohydrate-binding properties of a novel lectin family. We describe also the antibacterial, antifungal, and antiproliferative activities of these lectins and report about dependence of activities on molecular properties. Summarizing, CGL, MTL, and MytiLec-1 could be involved in the immunity in mollusks and may become a basis for the elaboration of new diagnostic tools or treatments for a variety of cancers.
Diversified carbohydrate-binding lectins from marine resources
Journal of amino acids, 2011
Marine bioresources produce a great variety of specific and potent bioactive molecules including natural organic compounds such as fatty acids, polysaccharides, polyether, peptides, proteins, and enzymes. Lectins are also one of the promising candidates for useful therapeutic agents because they can recognize the specific carbohydrate structures such as proteoglycans, glycoproteins, and glycolipids, resulting in the regulation of various cells via glycoconjugates and their physiological and pathological phenomenon through the host-pathogen interactions and cell-cell communications. Here, we review the multiple lectins from marine resources including fishes and sea invertebrate in terms of their structure-activity relationships and molecular evolution. Especially, we focus on the unique structural properties and molecular evolution of C-type lectins, galectin, F-type lectin, and rhamnose-binding lectin families.
Marine Drugs, 2016
MytiLec is an α-D-galactose-binding lectin with a unique primary structure isolated from the Mediterranean mussel (Mytilus galloprovincialis). The lectin adopts a β-trefoil fold that is also found in the B-sub-unit of ricin and other ricin-type (R-type) lectins. We are introducing MytiLec(-1) and its two variants (MytiLec-2 and-3), which both possess an additional pore-forming aerolysin-like domain, as members of a novel multi-genic "mytilectin family" in bivalve mollusks. Based on the full length mRNA sequence (911 bps), it was possible to elucidate the coding sequence of MytiLec-1, which displays an extended open reading frame (ORF) at the 5 1 end of the sequence, confirmed both at the mRNA and at the genomic DNA sequence level. While this extension could potentially produce a polypeptide significantly longer than previously reported, this has not been confirmed yet at the protein level. MytiLec-1 was revealed to be encoded by a gene consisting of two exons and a single intron. The first exon comprised the 5 1 UTR and the initial ATG codon and it was possible to detect a putative promoter region immediately ahead of the transcription start site in the MytiLec-1 genomic locus. The remaining part of the MytiLec-1 coding sequence (including the three sub-domains, the 3 1 UTR and the poly-A signal) was included in the second exon. The bacteriostatic activity of MytiLec-1 was determined by the agglutination of both Gram-positive and Gram-negative bacteria, which was reversed by the co-presence of α-galactoside. Altogether, these data support the classification of MytiLec-1 as a member of the novel mytilectin family and suggest that this lectin may play an important role as a pattern recognition receptor in the innate immunity of mussels.
Isolation and general characteristics of lectin from the mussel Mytilus trossulus
Chemistry of Natural Compounds, 2013
Lectin (MTL) of molecular weight 16,492 Da and pI 6.09 ± 0.01 that was most active in the pH range 9.0-10.0, was thermally labile, and did not require Ca 2+ for activation was isolated from the mussel Mytilus trossulus. The MTL was a Gal/GalNAc-specific lectin that exhibited an affinity for glycoproteins containing mucin-type chains. The cross reactivity between MTL and a lectin isolated from the mussel Crenomytilus grayanus was determined. It was shown that MTL at high concentration stimulated expression of TNF-D and IFN-J; at low concentration, exhibited immunomodulating activity by reducing hyperexpression of cytokine IL-10.