Three-dimensional structure and ligand-binding site of carp fishelectin (FEL)

CAPALDI, STEFANO; FAGGION, BENIAMINO; CARRIZO, MARÍA E.; DESTEFANIS, LAURA; GONZÁLEZ, MARÍA C.; PERDUCA, MASSIMILIANO; BOVI, MICHELE; GALLIANO, MONICA; MONACO, HUGO L.

WILEY-BLACKWELL PUBLISHING, INC

Año: 2015 vol. 71 p. 1123 - 1123

arp FEL (fishelectin or fish-egg lectin) is a 238-amino-acid lectin that can be purified from fish eggs by exploiting its selective binding to Sepharose followed by elution with N-acetylglucosamine. Its amino-acid sequence and other biochemical properties have previously been reported. The glycoprotein has four disulfide bridges and the structure of the oligosaccharides linked to Asn27 has been described. Here, the three-dimensional structures of apo carp FEL (cFEL) and of its complex with N-acetylglucosamine determined by X-ray crystallography at resolutions of 1.35 and 1.70 Å, respectively, are reported. The molecule folds as a six-bladed β-propeller and internal short consensus aminoacid sequences have been identified in all of the blades. A calcium atom binds at the bottom of the funnel-shaped tunnel located in the centre of the propeller. Two ligand-binding sites, α and β, are present in each of the two protomers in the dimer. The first site, α, is closer to t