A new multimeric hemagglutinin from the coelomic fluid of the sea urchin Anthocidaris crassispina.

A hemagglutinin was purified from the coelomic fluid of the sea urchin Anthocidaris crassispina by ion-exchange chromatography on DEAE-cellulose and affinity adsorption to glutaraldehyde-fixed ghosts of human erythrocytes, followed by elution with 10 mM EDTA. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it showed a single protein band with a molecular weight of 13 000 and 26 000 in the presence and absence of 2-mercaptoethanol, respectively. The molecular weight of the native protein with a hemagglutinating activity was determined to be 300 000 by sedimentation equilibrium analysis. Its sedimentation coefficient, S0(20),w, and Stokes radius were 13.7 S and 5.5 nm, respectively. The hemagglutinating activity of this protein required calcium ions. When calcium ions were depleted, no activity was observed and its sedimentation coefficient, S0(20),w, decreased to 11.4 S while its Stokes radius increased to 6.7 nm without a change in its molecular weight. The purified hemagglutinin agglutinated human erythrocytes regardless of their ABO and MN blood types. The hemagglutination reaction was not affected appreciably by various simple sugars but was inhibited by tryptic fragments released from human erythrocyte membranes. The results of alkaline borohydride treatment of the inhibitory tryptic fragments showed that the receptor sites for this hemagglutinin were mainly composed of alkali-labile carbohydrate chains with the structure AcNeu alpha 2----3Gal beta 1----3(AcNeu alpha 2----6)GalNAc----serine (or threonine).(ABSTRACT TRUNCATED AT 250 WORDS)