Allosteric regulation of the carbohydrate-binding ability of a novel conger eel galectin by D-mannoside

Mizuki Watanabe, Osamu Nakamura, Koji Muramoto, Tomohisa Ogawa

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    15 Citations (Scopus)


    Conger eel has two galectins, termed congerins I and II (Con I and II), that function in mucus as biodefense molecules. Con I and II have acquired a novel protein fold via domain swapping and a new ligand-binding site by accelerated evolution, which enables recognition of some marine bacteria. In this study, we identified a new congerin isotype, congerin P (Con-P), from the peritoneal cells of conger eel. Although Con-P displayed obvious homology with galectins, we observed substitution of 7 out of 8 amino acid residues in the carbohydrate recognition domain that are conserved in all other known galectins. To understand the structure-function relationships of this unique galectin, recombinant Con-P was successfully expressed in Escherichia coli by using a Con II-tagged fusion protein system and subsequently characterized. In the presence of D-mannose, Con-P displayed 30-fold greater hemagglutinating activity than Con I; however, no activity was observed without mannose, indicating that D-mannoside can act as a modulator of Con-P. Frontal affinity chromatography analysis showed that activated Con-P, allosterically induced by mannose, displayed affinity for oligomannose-type sugars as well as N-acetyllactosamine- type β-galactosides. Thus, Con-P represents a new member of the galectin family with unique properties.

    Original languageEnglish
    Pages (from-to)31061-31072
    Number of pages12
    JournalJournal of Biological Chemistry
    Issue number37
    Publication statusPublished - 2012 Sept 7

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology


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