Natural occurrence of microcystin synthetase deletion mutants capable of producing microcystins in strains of the genus Anabaena (Cyanobacteria)

David P Fewer, Ave Tooming-Klunderud, Jouni Jokela, Matti Wahlsten, Leo Rouhiainen, Tom Kristensen, Thomas Rohrlack, Kjetill S Jakobsen, Kaarina Sivonen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Microcystins form a large family of small cyclic heptapeptides harbouring extensive modifications in amino acid residue composition and functional group chemistry. These peptide hepatotoxins contain a range of non-proteinogenic amino acids and unusual peptide bonds, and are typically N-methylated. They are synthesized on large enzyme complexes consisting of non-ribosomal peptide synthetases and polyketide synthases in a variety of distantly related cyanobacterial genera, Here we report a 1236 bp in-frame deletion mutation in the mcyA gene of the microcystin biosynthetic pathway in nine strains of the genus Anabaena. The deletion removed almost the entire N-methyltransferase (NMT) domain. Strains of Anabaena carrying the in-frame deletion mutation incorporated mainly dehydroalanine (Dha) into the microcystins they produce while strains with full-length mcyA genes incorporated mainly N-methyldehydroalanine (Mdha). Interestingly, the strains of Anabaena lacking the NMT domain also incorporated elevated amounts Of L-Ser, the precursor of Mdha and Dha, into the microcystin they produced relative to strains carrying functional NMT domains. We provide evidence for the in-frame deletion of the NMT domain without the co-conversion of the flanking adenylation domain. Our results demonstrate a further example of the strategies employed by cyanobacteria in the biosynthesis of microcystin variants.
Original languageEnglish
JournalMicrobiology
Volume154
Issue number4
Pages (from-to)1007-1014
Number of pages8
ISSN1350-0872
DOIs
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed

Cite this

Fewer, David P ; Tooming-Klunderud, Ave ; Jokela, Jouni ; Wahlsten, Matti ; Rouhiainen, Leo ; Kristensen, Tom ; Rohrlack, Thomas ; Jakobsen, Kjetill S ; Sivonen, Kaarina. / Natural occurrence of microcystin synthetase deletion mutants capable of producing microcystins in strains of the genus Anabaena (Cyanobacteria). In: Microbiology. 2008 ; Vol. 154, No. 4. pp. 1007-1014.
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abstract = "Microcystins form a large family of small cyclic heptapeptides harbouring extensive modifications in amino acid residue composition and functional group chemistry. These peptide hepatotoxins contain a range of non-proteinogenic amino acids and unusual peptide bonds, and are typically N-methylated. They are synthesized on large enzyme complexes consisting of non-ribosomal peptide synthetases and polyketide synthases in a variety of distantly related cyanobacterial genera, Here we report a 1236 bp in-frame deletion mutation in the mcyA gene of the microcystin biosynthetic pathway in nine strains of the genus Anabaena. The deletion removed almost the entire N-methyltransferase (NMT) domain. Strains of Anabaena carrying the in-frame deletion mutation incorporated mainly dehydroalanine (Dha) into the microcystins they produce while strains with full-length mcyA genes incorporated mainly N-methyldehydroalanine (Mdha). Interestingly, the strains of Anabaena lacking the NMT domain also incorporated elevated amounts Of L-Ser, the precursor of Mdha and Dha, into the microcystin they produced relative to strains carrying functional NMT domains. We provide evidence for the in-frame deletion of the NMT domain without the co-conversion of the flanking adenylation domain. Our results demonstrate a further example of the strategies employed by cyanobacteria in the biosynthesis of microcystin variants.",
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Natural occurrence of microcystin synthetase deletion mutants capable of producing microcystins in strains of the genus Anabaena (Cyanobacteria). / Fewer, David P; Tooming-Klunderud, Ave; Jokela, Jouni; Wahlsten, Matti; Rouhiainen, Leo; Kristensen, Tom; Rohrlack, Thomas; Jakobsen, Kjetill S; Sivonen, Kaarina.

In: Microbiology, Vol. 154, No. 4, 2008, p. 1007-1014.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Natural occurrence of microcystin synthetase deletion mutants capable of producing microcystins in strains of the genus Anabaena (Cyanobacteria)

AU - Fewer, David P

AU - Tooming-Klunderud, Ave

AU - Jokela, Jouni

AU - Wahlsten, Matti

AU - Rouhiainen, Leo

AU - Kristensen, Tom

AU - Rohrlack, Thomas

AU - Jakobsen, Kjetill S

AU - Sivonen, Kaarina

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N2 - Microcystins form a large family of small cyclic heptapeptides harbouring extensive modifications in amino acid residue composition and functional group chemistry. These peptide hepatotoxins contain a range of non-proteinogenic amino acids and unusual peptide bonds, and are typically N-methylated. They are synthesized on large enzyme complexes consisting of non-ribosomal peptide synthetases and polyketide synthases in a variety of distantly related cyanobacterial genera, Here we report a 1236 bp in-frame deletion mutation in the mcyA gene of the microcystin biosynthetic pathway in nine strains of the genus Anabaena. The deletion removed almost the entire N-methyltransferase (NMT) domain. Strains of Anabaena carrying the in-frame deletion mutation incorporated mainly dehydroalanine (Dha) into the microcystins they produce while strains with full-length mcyA genes incorporated mainly N-methyldehydroalanine (Mdha). Interestingly, the strains of Anabaena lacking the NMT domain also incorporated elevated amounts Of L-Ser, the precursor of Mdha and Dha, into the microcystin they produced relative to strains carrying functional NMT domains. We provide evidence for the in-frame deletion of the NMT domain without the co-conversion of the flanking adenylation domain. Our results demonstrate a further example of the strategies employed by cyanobacteria in the biosynthesis of microcystin variants.

AB - Microcystins form a large family of small cyclic heptapeptides harbouring extensive modifications in amino acid residue composition and functional group chemistry. These peptide hepatotoxins contain a range of non-proteinogenic amino acids and unusual peptide bonds, and are typically N-methylated. They are synthesized on large enzyme complexes consisting of non-ribosomal peptide synthetases and polyketide synthases in a variety of distantly related cyanobacterial genera, Here we report a 1236 bp in-frame deletion mutation in the mcyA gene of the microcystin biosynthetic pathway in nine strains of the genus Anabaena. The deletion removed almost the entire N-methyltransferase (NMT) domain. Strains of Anabaena carrying the in-frame deletion mutation incorporated mainly dehydroalanine (Dha) into the microcystins they produce while strains with full-length mcyA genes incorporated mainly N-methyldehydroalanine (Mdha). Interestingly, the strains of Anabaena lacking the NMT domain also incorporated elevated amounts Of L-Ser, the precursor of Mdha and Dha, into the microcystin they produced relative to strains carrying functional NMT domains. We provide evidence for the in-frame deletion of the NMT domain without the co-conversion of the flanking adenylation domain. Our results demonstrate a further example of the strategies employed by cyanobacteria in the biosynthesis of microcystin variants.

U2 - 10.1099/mic.0.2007/016097-0

DO - 10.1099/mic.0.2007/016097-0

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SP - 1007

EP - 1014

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