[ d-Leu 1] microcystin-LR, a new microcystin isolated from waterbloom in a Canadian prairie lake

• Published in: Toxicon (Oxford) Vol. 39; no. 6; pp. 855 - 862
• Main Authors: Park, H, Namikoshi, M, Brittain, S.M, Carmichael, W.W, Murphy, T
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2001; Elsevier Science
• Subjects: [ d-Leu 1]microcystin-LR; Bacteriology; Biological and medical sciences; Canada; Cyanobacteria; Cyanophyta; Cyanotoxins; Fundamental and applied biological sciences. Psychology; Lake Pakowki; Microbiology; Microcystin; Microcystis; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Canada; North America; America; Canada, Alberta, Pakowki L; Microcystin; Canada; Lake Pakowki; [ d-Leu 1]microcystin-LR; Cyanobacteria; Cyanotoxins; Molecular structure; Toxicity; Mortality; Freshwater environment; Toxin; Vertebrata; Microbial origin; Animal; Bloom; Lakes; Bacteria; Aves; Aminoacid sequence; Structural analysis
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/S0041-0101(00)00224-5

A previously undescribed cyclic heptapeptide hepatotoxin was isolated from a cyanobacteria waterbloom collected in Pakowki Lake, Alberta, Canada (49°20′N and 110°55′W). The compound was characterized by amino acid analysis, ESIMS/CID/MS, 1H and 13C NMR, and UV spectroscopy. Structure of the new microcystin was assigned as [ d-Leu 1]microcystin-LR ( 1). The amino acid composition is the same as microcystin-LR ( 2) except for d-Leu and l-Leu in 1 instead of d-Ala and l-Leu in 2. This is the first microcystin identified, among the 64 known microcystins, that has both a d- and l-Leu amino acid. Toxicity as measured by the protein phosphatase inhibition activity of 1 is similar to microcystin-LR. The presence of microcystins in waterblooms from this lake is discussed in relation to the almost yearly bird mortalities that have occurred there since 1995.