title: [The effect of chemical modification on the immunochemical activity of Rm-III neurotoxin from the anemone Radiantus macrodactylus].
abstract: A chemical modification was used for studying the organization of antigenic determinants of neurotoxin Rm-III from the sea anemone Radianthus macrodactylus. Immunochemical experiments were performed using competitive enzyme-linked immunosorbent assay (ELISA) with polyclonal antibodies to Rm-III. The modification affected N-terminal amino group of Gly1, Lys4, Arg13, Trp30 residues, a residue in the Lys46-Lys47-Lys48 sequence, two different residues in the Asp6-Asp7-Glu8 sequence in two samples of the toxin, and two disulphide bonds. Only the modification of the disulphide bonds led to a considerable change in the toxin's affinity to antibodies. The modification of Trp30 resulted in two-fold decrease of the toxin concentration necessary for 50% inhibition of the test-system, whereas upon modification of any other amino acid residue this concentration increased but not more than by 2.2 times. It is suggested that Rm-III sequence lacks individual residues which are of great importance for the toxin's antigenic activity, its conformation being of vital importance for the formation of the toxin's antigenic determinants.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D003064:Cnidarian Venoms; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D007120:Immunochemistry; D009498:Neurotoxins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D012615:Sea Anemones / Q000737:chemistry*
chemical_list: D003064:Cnidarian Venoms; D000939:Epitopes; D009498:Neurotoxins; C078748:neurotoxin III, Radianthus macrodactylus
vernacular_title: Vliianie khimicheskoĭ modifikatsii na immunokhimicheskuiu aktivnost' neĭrotoksina Rm-III iz aktinii Radiantus macrodactylus.