title: Nontoxic and toxic oligopeptides with D-amino acids and unusual residues in Microcystis aeruginosa PCC 7806.
abstract: Toxic and nontoxic peptides were isolated from the cyanobacterium Microcystis aeruginosa PCC 7806 by a procedure including extraction of cells with water-saturated 1-butanol, chromatography of the extract on silica gel plates and high performance liquid chromatography (HPLC) on Partisil-5. The toxin was shown to be only a minor constituent, being negatively charged and thus separable by electrophoresis, within the HPLC-purified fraction. It contained erythro-beta-methyl-D-Asp, D-Glu, D-Ala, L-Leu, and L-Arg known to be part of the Microcystis peptide-toxin with Mr 994. The major part of the HPLC-purified fraction was assigned, however, to a nontoxic peptide with a Mr of 956. Partial hydrolysis studies of the nontoxic peptide(s) revealed amino acid sequences composed of D-Glu, N-methyl-Phe, and 3,4-dehydro-Pro, aside from the common L-amino acids. Cyclic linkage in the nontoxic peptide(s) appears likely.
authors.affiliation: Institut für Biologie II, Albert-Ludwigs-Universität, Freiburg, Federal Republic of Germany.
authors.forename: I M
authors.initials: IM
authors.lastname: Birk
authors.forename: R
authors.initials: R
authors.lastname: Dierstein
authors.forename: I
authors.initials: I
authors.lastname: Kaiser
authors.forename: U
authors.initials: U
authors.lastname: Matern
authors.forename: W A
authors.initials: WA
authors.lastname: König
authors.forename: R
authors.initials: R
authors.lastname: Krebber
authors.forename: J
authors.initials: J
authors.lastname: Weckesser
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D015180:Electrophoresis, Gel, Two-Dimensional; D004590:Electrophoresis, Paper; D008401:Gas Chromatography-Mass Spectrometry; D006868:Hydrolysis; D013058:Mass Spectrometry; D046931:Microcystis / Q000032:analysis*; D009842:Oligopeptides / Q000032:analysis / Q000302:isolation & purification*; D013056:Spectrophotometry, Ultraviolet; D014118:Toxins, Biological / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D009842:Oligopeptides; D014118:Toxins, Biological