Details

Autor(en) / Beteiligte

• Watanabe, Mizuki
• Nakamura, Osamu
• Muramoto, Koji
• Ogawa, Tomohisa

Titel

Allosteric Regulation of the Carbohydrate-binding Ability of a Novel Conger Eel Galectin by d-Mannoside

Ist Teil von

• The Journal of biological chemistry, 2012-09, Vol.287 (37), p.31061-31072

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2012

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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. Background: Galectins from peritoneal cells of conger eel contribute to the encapsulation of nematode. Results: A new galectin from peritoneal cells, congerin P (Con-P), shows unusual sequence, specificity, and allosteric regulation by mannoside. Conclusion: Con-P is a new type of galectin with allosteric carbohydrate-binding ability. Significance: Con-P is the first known lectin allosterically modulated by its ligands.