The Primary Structure and Carbohydrate Specificity of a β-Galactosyl-binding Lectin from Toad (Bufo arenarum Hensel) Ovary Reveal Closer Similarities to the Mammalian Galectin-1 than to the Galectin from the Clawed Frog Xenopus laevis

Abstract

The detailed characterization of a galectin from the toad (Bufo arenarum Hensel) ovary in its primary structure, carbohydrate specificity, and overall biochemical properties has provided novel information pertaining to structural and evolutionary aspects of the galectin family. The lectin consists of identical single-chain polypeptide subunits composed of 134 amino acids (calculated mass, 14,797 daltons), and its N-terminal residue, alanine, is N-acetylated. When compared to the sequences of known galectins, the B. arenarum galectin exhibited the highest identity (48% for the whole molecule and 77% for the carbohydrate recognition domain (CRD)) with the bovine spleen galectin-1, but surprisingly less identity (38% for the whole molecule and 47% for the CRD) with a galectin from Xenopus laevis skin (Marschal, P., Herrmann, J., Leffler, H., Barondes, S. H., and Cooper, D. N. W. (1992) J. Biol. Chem. 267, 12942-12949). Unlike the X. laevis galectin, the binding activity of the B. arenarum galectin for N-acetyllactosamine, the human blood group A tetrasaccharide and Gal␤1,3GalNAc relative to lactose, was in agreement with that observed for the galectin-1 subgroup and those galectins having "conserved" (type I) CRDs (Ahmed, H., and Vasta, G. R. (1994) Glycobiology 4, 545-549). Moreover, the toad galectin shares three of the six cysteine residues that are conserved in all mammalian galectins-1, but not in the galectins from X. laevis, fish, and invertebrates described so far. Based on the homologies of the B. arenarum galectin with the bovine spleen galectin-1 and X. laevis skin galectin, it should be concluded that within the galectin family the correlation between conservation of primary structure and phylogenetic distances among the source species may not be a direct one as proposed elsewhere (Hirabayashi, J., and Kasai, K. (1993) Glycobiology 3, 297-304). Furthermore, galectins with conserved (type I) CRDs, represented by the B. arenarum ovary galectin, and those with "variable" (type II) CRDs, represented by the X. laevis 16-kDa galectin, clearly constitute distinct subgroups in the extant amphibian taxa and may have diverged early in the evolution of chordate lineages.

High-Level Expression of Human Liver Monoamine Oxidase B in Pichia pastoris

“…Twenty-five percent of eluted homoserine and homoserine lactone forms of the N-terminal peptides was analyzed by nano-ESI-MS-MS. The doubly charged species were selected for fragmentation (collision energy 25-50 eV, collision gas N 2 at instrument pressure setting 5) and the quadrupole was scanned from 100 to 1550 amu with 0.1-amu step and a dwell time of 0.5 s. Fifty percent of the eluted homoserine form of the N-terminal peptide was treated with 100% TFA for 2 h to induce an N-O shift of the acetyl group and generate a free N-terminus (28,29). This sample was then subjected to Edman degradation.…”

Cloning and characterisation of tandem-repeat type galectin in rainbow trout (Oncorhynchus mykiss)

“…Besides mammalian galectin, the galectin family has been reported in nematodes (Hirabayashi et al, 1992a(Hirabayashi et al, , 1996, fish (Muramoto & Kamiya, 1992), 218 frogs (Ahmed et al, 1996) and chicken (Schneller et al, 1995). In fish, conger eel and electric eel have the proto-type galectin homologous protein and/or gene (Paroutaud et al, 1987;Muramoto & Kamiya, 1992;Ogawa et al, 1999).…”

Nodavirus Infection of Sea Bass (Dicentrarchus labrax) Induces Up-Regulation of Galectin-1 Expression with Potential Anti-Inflammatory Activity

“…The presence of abundant 30-and 45-kDa oligomers in the rSbgalectin-1 control, however, suggests that strong hydrophobic interactions take place among its subunits and opens the possibility that the monomers and oligomers (15,30, and 45 kDa) are potentially functional protein species in the infected tissues. This may reflect structural differences in the Sbgalectin-1 folding relative to that reported for the mammalian prototype galectins (55,56) and is consistent with the 45-kDa species observed in the infected animals, Moreover, the lack of the 30-kDa dimer in the latter suggests that the Sbgalectin-1 trimerization may be specific to the nodavirus infection in brain, an intriguing observation that warrants further investigation.…”