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.
Department of Biology, Biotechnical Faculty, University of Ljublijana, Slovenia, Yugoslavia.
T
T
Turk
P
P
Macek
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