A Unique 2-Sulfated β-Galactan from the Egg Jelly of the Sea Urchin Glyptocidaris crenularis

Abstract

Sulfated polysaccharides from the egg jelly of sea urchins act as species-specific inducers of the sperm acrosome reaction, which is a rare molecular mechanism of carbohydrate-induced signal-transduction event in animal cells. The sea urchin polysaccharides differ in monosaccharide composition (L-fucose or L-galactose), glycosylation, and sulfation sites, but they are always in the ␣-anomeric configuration. Herein, structural analysis of the polysaccharide from the sea urchin Glyptocidaris crenularis surprisingly revealed a unique sulfated ␤-D-galactan composed by (3-␤-D-Galp-2(OSO 3 )-133-␤-D-Galp-1) n repeating units. Subsequently, we used the G. crenularis galactan to compare different 2-sulfated polysaccharides as inducers of the acrosome reaction using homologous and heterologous sperm. We also tested the effect of chemically over-sulfated galactans. Intriguingly, the anomeric configuration of the glycosidic linkage rather than the monosaccharide composition (galactose or fucose) is the preferential structural requirement for the effect of these polysaccharides on sea urchin fertilization. Nuclear magnetic resonance and molecular dynamics indicate that sulfated ␣-galactan or ␣-fucan have less dynamic structural behavior, exhibiting fewer conformational populations, with an almost exclusive conformational state with glycosidic dihedral angles ⌽/⌿ ‫؍‬ ؊102°/131°. The preponderant conformer observed in the sulfated ␣-galactan or ␣-fucan is not observed among populations in the ␤-form despite its more flexible structure in solution. Possibly, a proper spatial arrangement is required for interaction of the sea urchin-sulfated polysaccharides with the specific sperm receptor.The evolution of barriers to inter-specific hybridization is a crucial step in the fertilization of free-spawning marine invertebrates. In sea urchins the molecular recognition between sperm and egg ensures species recognition. The jelly coat surrounding sea urchin eggs is not a simple accessory structure; it is considerably complex on a molecular level and intimately involved in gamete recognition. It contains sulfated polysaccharides, sialoglycans, and peptides.Structural changes in the sulfated polysaccharide from the egg jelly of sea urchins modulate cell-cell recognition and species specificity leading to exocytosis of the acrosomal vesicle, the acrosome reaction. This is a crucial event for the recognition between male and female gametes, leading to the fertilization success, and is also what prevents intercrosses. The sulfated polysaccharide from the egg jelly recognizes its specific receptor present in the sperm. Apart from the sialoglycans that act in synergy with the sulfated polysaccharides, other components of the egg jelly do not possess acrosome reaction-inducing activity (1). The sulfated polysaccharide-mediated mechanism of sperm-egg recognition co-exists with that of bindin and its receptor in the egg (2-4).The sulfated polysaccharides from sea urchin show speciesspecific structures composed of repetitive units (mono-, tri-, ...

Bovine and porcine heparins: different drugs with similar effects on human haemodialysis

“…The pharmaceutical preparations of bovine and porcine heparin used in this study were analyzed by one-dimensional (1D) 1 H NMR spectra, as described [5,13]. Approximately 0.4 mL of the pharmaceutical preparations, containing ~10 mg of heparin, were lyophilized and dissolved in 0.5 mL of 99.9% deuterium oxide (Cambridge Isotope Laboratory, Cambridge, MA, USA).…”

Sperm and Egg Jelly Coat from Sea Urchin Lytechinus variegatus Collected in Rio de Janeiro Contain Distinct Sialic Acid-Rich Polysaccharides

“…These sialic acidrich molecules potentiate the acrosome reaction in the sea urchin sperm, which is induced in a species-specific way by the egg jelly sulfated polysaccharides (Hirohashi and Vacquier 2002). Interestingly, one particular species of sea urchin, Glyptocidaris crenularis, sialic acid-rich polysaccharide is absent in the egg jelly (Castro et al 2009). Several studies have been conducted on the characterization of sulfated polysaccharides from the egg jelly coat of sea urchins and characterized the unique polysaccharide structures of welldefined units, composed of sulfated fucose or sulfated galactose (Alves et al 1998;Vilela-Silva et al 1999.…”

Specific sulfation and glycosylation—a structural combination for the anticoagulation of marine carbohydrates

“…The sulfation groups are highlighted by red dashed ellipses or rectangle when just percentage can be estimated. The structures are the following: (A) Ludwgothurea grisea [→3)-α-L-Fuc p -2,4(OSO 3− )-(1→3)-α-L-Fuc p -(1→3)-α-L-Fuc p -2(OSO 3− )-(1→3)-α-L-Fuc p -2(OSO 3− )-(1→] n (Mulloy et al, 1994); (B) Lytechinus variegates I [→3)-α-L-Fuc p -2,4(OSO 3− )-(1→3)-α-L-Fuc p -2(OSO 3− )-(1→3)-α-L-Fuc p -2(OSO 3− )-(1→3)-α-L-Fuc p -4(OSO 3− )-(1→] n (Mulloy et al, 1994); (C) Strongylocentrotus pallidus [→3)-α-L-Fuc p -4(OSO 3− )-(1→3)-α-L-Fuc p -4(OSO 3− )-(1→3)-α-L-Fuc p- 2(OSO 3− )-(1→3)-α-L-Fuc p- 2(OSO 3− )-(1→] n (Vilela-Silva et al, 2002); (D) Arbacia lixula [→4)-α-L-Fuc p -2(OSO 3− )-(1→4)-α-L-Fuc p -2(OSO 3− )-(1→4)-α-L-Fuc p -(1→4)-α-L-Fuc p -(1→] n (Alves et al, 1997); (E) Strongylocentrotus purpuratus I ~80% [→3)-α-L-Fuc p -2,4(OSO 3− )-(1→] n and ~20% [→3)-α-L-Fuc p -2(OSO 3− )-(1→] n (Alves, Mulloy, Moy, Vacquier and Mourão, 1998) and (F) S. purpuratus II [→3)-α-L-Fuc p -2,4(OSO 3− )-(1→3)-α-L-Fuc p -4(OSO 3− )-(1→3)-α-L-Fuc p -4(OSO 3− )-(1→] n (Alves, Mulloy, Moy, Vacquier and Mourão, 1998); (G) Strongylocentrotus droebachiensis [→4)-α-L-Fuc p -2(OSO 3− )-(1→] n (Vilela-Silva et al, 2002); (H) Strongylocentrotus franciscanus [3)-α-L-Fuc p -2(OSO 3− )-(1→] n (Vilela-Silva et al, 1999); (I) L. varieagtus II [3)-α-L-Fuc p -4(OSO 3− )-(1→] n (Cinelli et al, 2007); (J) Echinometra lucunter [→3-α-L-Gal p -2(OSO 3− )-1→] n (Alves et al, 1997); (K) Glyptocidaris crenularis [→3-β-L-Gal p -2(OSO 3− )-1→3-β-L-Gal p -1→] n (Castro et al, 2009); (L) Herdmania monus [→4)-α-L-Gal p -3(SO 3− )-(1→] n (Santos et al, 1992); (M) Styela plicata {→4)-α-L-Gal p -2[→1)- α-L-Gal p -3(OSO 3− )]-3(OSO 3− )-(1→} n (Mourão and Perlin, 1987); (N,O) both Botriocladia occidentalis and Gelidium crinale express structures of [3-β-D-Gal p -1→4-α-Gal-1→] n with different sulfation contents (Farias et al, 2000; Pereira et al, 2005b). …”