title: Synthesis and characterization of a chimeric peptide derived from fasciculin that inhibits acetylcholinesterase.
abstract: Fasciculins are peptides isolated from mamba (Dendroaspis) venoms which exert their toxic action by inhibiting acetylcholinesterase (AChE). They contain a characteristic triple stranded antiparallel beta-sheet formed by residues 22-27, 34-39 and 48-53. A chimeric peptide named Fas-C, encompassing most of these sequences was synthesized using SPPS/Boc-chemistry and characterized chemically, structurally and functionally. Fas-C has two disulfide bridges, formed sequentially using dual cysteine protection. SDS-PAGE patterns, HPLC profiles and MS proved the peptide identity. Circular dichroism indicated the presence of 13.6% and 41.6% of beta-sheet and beta-turn, respectively, comparable to values observed in the native toxin. An inhibitory effect on eel AChE was displayed by the peptide (Ki71.6 +/- 18.3 microM), although not reaching the affinity level of the parent native toxin (Ki 0.3 nM). It is confirmed that the principal binding region of fasciculin to AChE resides within loop II.
authors.affiliation: Instituto de Química y Fisicoquímica Biológicas, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 956, 1113-Buenos Aires, Argentina.
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Falkenstein
authors.forename: Germán G
authors.initials: GG
authors.lastname: Gornalusse
authors.forename: Clara
authors.initials: C
authors.lastname: Peña
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry; D000595:Amino Acid Sequence; D002800:Cholinesterase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D002918:Chymotrypsin / Q000737:chemistry; D004546:Elapid Venoms / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D000085822:Prolyl Oligopeptidases; D017433:Protein Structure, Secondary; D012697:Serine Endopeptidases / Q000737:chemistry
chemical_list: D002800:Cholinesterase Inhibitors; D004546:Elapid Venoms; C495381:Fas-C chimeric peptide; D010455:Peptides; C044937:fasciculin; D000110:Acetylcholinesterase; D012697:Serine Endopeptidases; D002918:Chymotrypsin; D000085822:Prolyl Oligopeptidases