title: Purification and sequence determination of a new muscarinic toxin (MT4) from the venom of the green mamba (Dendroaspis angusticeps).
abstract: A toxin which partially inhibited [3H]N-methylscopolamine binding to rat brain muscarinic receptors was purified from the venom of green mamba, Dendroaspis angusticeps. The N-terminal sequence (up to 45 amino acids) was determined by automated Edman degradation of the whole molecule. The complete sequence was elucidated after enzymatic cleavage with endoproteinase Arg-C or endoproteinase Lys-C and peptide fragments purification. The identity of the C-terminal amino acid was confirmed by hydrazinolysis. The new toxin (MT4) had eight half-cystines and 66 amino acids. It differed from muscarinic toxin MT1 by a single substitution in position 57 (arginine in MT1, histidine in MT4), proximal to the sixth half-cystine.
authors.affiliation: Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Vandermeers
authors.forename: M C
authors.initials: MC
authors.lastname: Vandermeers-Piret
authors.forename: J
authors.initials: J
authors.lastname: Rathé
authors.forename: M
authors.initials: M
authors.lastname: Waelbroeck
authors.forename: M
authors.initials: M
authors.lastname: Jolkkonen
authors.forename: A
authors.initials: A
authors.lastname: Oras
authors.forename: E
authors.initials: E
authors.lastname: Karlsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D017815:Elapidae; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D019832:N-Methylscopolamine; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D010276:Parasympatholytics / Q000378:metabolism; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects*; D012602:Scopolamine Derivatives / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics; D014364:Tryptophan / Q000378:metabolism
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins; D010276:Parasympatholytics; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; C098184:muscarinic toxin MT4; D014364:Tryptophan; C044499:submandibular proteinase A; D012697:Serine Endopeptidases; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; D019832:N-Methylscopolamine