Purification and characterization of N‐glycolylneuraminic‐acid‐specific lectin from Scylla serrata

Abstract

A sialic-acid-binding lectin with specificity for N-glycolylneuraminic acid (NeuGc) was purified from the hemolymph of the marine crab Scyllu serrutu by affinity chromatography using thyroglobulin-coupled agarose. The binding specificity of Scyllu lectin distinguishes it from other known sialic-acid-specific lectins found in Limulus polyphemus and Limux fluvus, which show a broader range of specificity for sialic acids. The molecular mass of the purified lectin is about 55 kDa.Under reducing conditions (SDWPAGE), it resolved into two subunits of 30 kDa and 25 kDa. NeuGc inhibited hemagglutination activity of the purified lectin at a concentration as low as 0.6 mM, whereas N-acetylneuraminic acid (NeuAc) even at a concentration of 100 mM, failed to inhibit hemagglutination. This finding was supported by potent inhibition of hemagglutination by bovine and porcine thyroglobulins, which contain a NeuGca2-6Gal as terminal component of oligosaccharide residues. Neither glycoproteins (glycophorin NN; porcine submaxillary mucin), which contain NeuAca2-3Gal/GalNAc and NeuAca2-6GalNAc, nor human acid glycoprotein, which contains NeuAca2-3/a2-6 Gal, or colominic acid, a sialopolymer with NeuAca2-8NeuAc, inhibited the lectin activity. The specificity of the lectin for NeuGc appears to account for the fact that it agglutinates rabbit and mice erythrocytes, but not human A, 0, AB, rat or chicken erythrocytes, which contain NeuAc. The inability of the lectin to agglutinate erythrocytes (horse) that prominently express NeuGc could be due to 0-acetylation of NeuGc. In support of this, bovine submaxillary mucin, which contains 0-acetylated NeuGc inhibited the hemagglutination of the lectin better after removal of 0-acetyl groups by base treatment. The unique specificity of Scyllu lectin is of diagnostic potential for human cancer tissues expressing NeuGc, since NeuGc is not found in normal human tissues.Invertebrate lectins may recognize a part of a sugar [l], a whole sugar [2], their glycosidic linkage [3-61, or a sequence of sugars [7, 81. Among invertebrates, arthropods and molluscs produce sialic-acid-specific lectins. Although crustaceans can not synthesize sialic acids [9, 101, they make sialic acid binding lectins as a defense against bacteria, which express a variety of sialoconjugates [l]. Plant lectins are not specific for sialic acids, and of the three sialic-acidbinding plant lectins, wheat germ agglutinin binds to GlcNAc [ l l ] and the other two recognize the glycosidic linkages of sialic acids [4-61. On the other hand, lectins purified from Limulus (horse-shoe crab) and Limux (slug) bind to NeuAc [l, 121, whereas Cancer (marine crab) lectin binds specifically to 0-acetylated sialic acids [l]. There are at least 18 different species of sialic acids in nature [13]. The type of sialic acid and the glycosidic linkages with the adjacent sugar in an oligosaccharide contribute to a remarkable diversity of Correspondence to Sister P. D. Mercy, Department of Zoology, Holy Cross College, Roche Nagar, Nagarcoil, Tamilnadu, I...

Characterisation of a natural haemagglutinin with affinity for acetylated aminosugars in the serum of the marine prawn, (H. Milne Edwards)

“…Previous studies on serum agglutinins from crustaceans have demonstrated their carbohydrate binding specificity for fucose (Amirante & Basso, 1984), galactose (Kamiya et al, 1987), GalNAc (Amirante & Basso, 1984), sucrose (Nalini et al, 1994) or sialic acids such as NeuAc (Hall & Rowlands, 1974;Muramoto et al, 1995), O-acetyl NeuAc (Ravindranath et al, 1985) and N-glycolylneuraminic acid (NeuGc; Mercy & Ravindranath, 1993). Furthermore, the serum agglutinins of lobster (LAg2; Hall & Rowlands, 1974), prawns (Ratanapo & Chulavatnatol, 1990;Vargas-Albores et al, 1993;Fragkiadakis & Stratakis, 1995) and crab (Cassels et al, 1986) appeared to recognise acetylated aminosugars, but their absolute specificity towards such sugars has not been thoroughly investigated.…”

Immune response and gene expression in shrimp (Litopenaeus vannamei) hemocytes and hepatopancreas against some pathogen-associated molecular patterns

“…These C-type lectins were reported to be involved in activation of proPO [41], antibacterial activation [42], encapsulation and phagocytosis [43][44][45][46][47] and many other various biological responses in invertebrates. In the present study, the variation of C-type lectin gene expression was detected by real-time RT-PCR in hemocytes and hepatopancreas after stimulation with the PAMPs.…”

Purification, Characterization, and Sugar Binding Specificity of an N-Glycolylneuraminic Acid-specific Lectin from the Mushroom Chlorophyllum molybdites

“…The lectin from the snail Pila globasal has specificity for NeuGc␣(236)GalNAc-ol Ͼ NeuGc Ͼ Ͼ NeuAc (17). NeuGc-specific lectins were also isolated from the crab Scylla serrata (18,19) and mulberry leaf (Morus alba) (MLL 1 and 2) (20).…”