When social groups monopolize discrete habitat patches, group size may be positively correlated with patch size. The correlation can be a direct consequence of limited resources. Alternatively, it can be an indirect consequence of patch-size effects on a dominant group member. We asked which of these two mechanisms was responsible for a positive correlation between the group size of false clown...

The voltage-gated Kv1.3 K(+) channel is a novel target for immunomodulation of autoreactive effector memory T (T(EM)) cells that play a major role in the pathogenesis of autoimmune diseases. We describe the characterization of the novel peptide ShK(L5) that contains l-phosphotyrosine linked via a nine-atom hydrophilic linker to the N terminus of the ShK peptide from the sea anemone Stichodactyl...

An immobilized biocatalyst (ShIE-Octyl) was obtained by interfacial adsorption on Octyl-Sepharose CL 4B support of all interfacial esterases from the aqueous extract of the sea anemone Stichodactyla helianthus. ShIE-Octyl, synthesized by this simple method, contains semipurified interfacial esterases, including the isotoxins StI and StII. The immobilized esterases are maximally stable at pH 7.0...

The BPTI/Kunitz-type inhibitor family includes several extremely potent serine protease inhibitors. To date, the inhibitory mechanisms have only been studied for mammalian inhibitors. Here, the first crystal structure of a BPTI/Kunitz-type inhibitor from a marine invertebrate (rShPI-1A) is reported to 2.5 Å resolution. Crystallization of recombinant rShPI-1A required the salt-induced dissociati...

The Caribbean Sea anemone Stichodactyla helianthus produces two pore-forming proteins, sticholysins I and II (StI and StII). To clarify the contribution of the fi rst thirty (StII) or thirty-one (StI) N-terminal amino acid residues to the activity of the toxins, four peptides spanning residues 1-31 of StI (StI1-31, StI12-31) and 1-30 of StII (StII1-30, StII11-30) were synthesized. StII1-30 was ...

Sea anemone cytolysins constitute a novel class of toxins that functions by forming channels in cell membranes. In contrast to the bacterial pore-forming toxins, there is little detailed information on the mechanism of action of these toxins and as yet no 3-D structures have been determined. These highly basic toxins of mass ∼20 kDa generate pores in membranes containing sphingomyelin by formin...

The major protease inhibitor from the sea anemone Stichodactyla helianthus (ShPI-1) is a non-specific inhibitor that binds trypsin and other trypsin-like enzymes, as well as chymotrypsin, and human neutrophil elastase. We performed site-directed mutagenesis of ShPI-1 to produce two variants (rShPI-1/K13L and rShPI/Y15S) that were expressed in Pichia pastoris, purified, and characterized. After ...