The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium
AbstractMicrocystins are a family of chemically diverse hepatotoxins produced by distantly related cyanobacteria and are potent inhibitors of eukaryotic protein phosphatases 1 and 2A. Here we provide evidence for the biosynthesis of rare variants of microcystin that contain a selection of homo-amino acids by the benthic strain Phormidium sp. LP904c. This strain produces at least 16 microcystin chemical variants many of which contain homophenylalanine or homotyrosine. We retrieved the complete 54.2 kb microcystin (mcy) gene cluster from a draft genome assembly. Analysis of the substrate specificity of McyB1 and McyC adenylation domain binding pockets revealed divergent substrate specificity sequences, which could explain the activation of homo-amino acids which were present in 31% of the microcystins detected and included variants such as MC-LHty, MC-HphHty, MC-LHph and MC-HphHph. The mcy gene cluster did not encode enzymes for the synthesis of homo-amino acids but may instead activate homo-amino acids produced during the synthesis of anabaenopeptins. We observed the loss of microcystin during cultivation of a closely related strain, Phormidium sp. DVL1003c. This study increases the knowledge of benthic cyanobacterial strains that produce microcystin variants and broadens the structural diversity of known microcystins.
- Supplementary File 1:
PDF-Document (PDF, 3600 KB)
Share & Cite This Article
Shishido, T.K.; Jokela, J.; Humisto, A.; Suurnäkki, S.; Wahlsten, M.; Alvarenga, D.O.; Sivonen, K.; Fewer, D.P. The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium. Mar. Drugs 2019, 17, 271.
Shishido TK, Jokela J, Humisto A, Suurnäkki S, Wahlsten M, Alvarenga DO, Sivonen K, Fewer DP. The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium. Marine Drugs. 2019; 17(5):271.Chicago/Turabian Style
Shishido, Tânia Keiko; Jokela, Jouni; Humisto, Anu; Suurnäkki, Suvi; Wahlsten, Matti; Alvarenga, Danillo O.; Sivonen, Kaarina; Fewer, David P. 2019. "The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium." Mar. Drugs 17, no. 5: 271.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.