The role of lysine, histidine and carboxyl residues in biological activity of equinatoxin II, a pore forming polypeptide from the sea anemone Actinia equina L.
Equinatoxin II, a pore forming polypeptide from the sea anemone Actinia equina L. was subjected to chemical modifications with group specific reagents. Lysine residues were modified with pyridoxal-5'-phosphate, histidine residues with diethyl pyrocarbonate and carboxyl groups with the use of a water soluble carbodiimide. Modification of charged residues had no significant influence on the toxin interaction with serum lipoproteins. Lysine 5'-phosphopyridoxylated and histidine carbethoxylated derivatives of the toxin retained lethal and hemolytic activities, but the pH profile of hemolytic activity of 5'-phospho-pyridoxylequinatoxin II was markedly altered. Modification of the toxin carboxyl groups impaired both hemolytic and lethal activities, the latter, however, to the greater extent.
Turk
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Department of Biology, Biotechnical Faculty, University of Ljublijana, Slovenia, Yugoslavia.
Macek
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D000818:Animals; D002417:Cattle; D003064:Cnidarian Venoms / Q000737:chemistry* / Q000494:pharmacology; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D006639:Histidine; D006801:Humans; D007202:Indicators and Reagents; D007525:Isoelectric Focusing; D008074:Lipoproteins / Q000097:blood*; D008239:Lysine; D008970:Molecular Weight; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D012615:Sea Anemones; D013053:Spectrophotometry
D003064:Cnidarian Venoms; D007202:Indicators and Reagents; D008074:Lipoproteins; D006639:Histidine; C012307:equinatoxin; D011732:Pyridoxal Phosphate; D008239:Lysine; D004047:Diethyl Pyrocarbonate