Identification and characterization of microcystin-LY from Microcystis aeruginosa (strain 298).
Two toxins, a main component A and a minor component B, were isolated from the freshwater cyanobacterium Microcystis aeruginosa (strain 298) and characterized in their chemical structure by amino-acid analysis, configurational analysis, by FAB-MS and 1H-NMR spectroscopy. The acid hydrolysate yielded for toxin A as constituent amino acids D-Ala, L-Leu, D-Glu, erythro-D-beta-Me-Asp and L-Arg, and for toxin B the amino acids D-Ala, L-Leu, D-Glu, erythro-D-beta-Me-Asp and L-Tyr. 1D and 2D 1H-NMR spectroscopy of the toxins A and B in DMSO-d6 allowed to characterize them as cyclic heptapeptides containing both the unusual beta-amino acid Adda (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid) and N-methyldehydroalanine (Mdha) as additional constituent residues. Toxin A was found to correspond to the known and structurally well characterized microcystin-LR and toxin B to microsystin-LY. The presence of this variant has already been proposed, but its primary structure could be confirmed in this study.
Rudolph-Böhner
S
S
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Wu
J T
JT
Moroder
L
L
D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D052998:Microcystins; D046931:Microcystis / Q000737:chemistry*; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000032:analysis*; D011487:Protein Conformation; D013057:Spectrum Analysis
D052998:Microcystins; D010456:Peptides, Cyclic; C084459:microcystin LY