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Isolation and structure determination of two microcystins and sequence comparison of the McyABC aenylation domains in Planktothrix species


Christiansen, G; Yoshida, W Y; Blom, J F; Portmann, C; Gademann, K; Hemscheidt, T; Kurmayer, R (2008). Isolation and structure determination of two microcystins and sequence comparison of the McyABC aenylation domains in Planktothrix species. Journal of Natural Products, 71(11):1881-1886.

Abstract

Microcystins (MCs) are toxic heptapeptides found in cyanobacteria and share the common structure cyclo(-D-Ala1-L-X2-D-isoMeAsp3-L-Z4-Adda5-D-isoGlu6-Mdha7). The letters X and Z in the general formula above represent a wide range of L-amino acids that occupy positions 2 and 4, respectively. In general the variation in structural variants is due to the exchange of amino acids in position 7, 2, and 4. In the present work we report two homotyrosine (Hty)-containing microcystin variants, [D-Asp3,(E)-Dhb7]-MC-HtyY (1) and [D-Asp3,(E)-Dhb7]-MC-HtyHty (2), which were isolated from strain No80 of Planktothrix rubescens. Their structures were elucidated using amino acid analysis as well as 1D- and 2D NMR techniques. The adenylation domains of McyABC involved in amino acid activation in positions 7, 2, and 4 of the microcystin molecule, respectively, were compared with corresponding genes of Planktothrix strain CYA126/8 producing [D-Asp3,Mdha7]-MC-RR and [D-Asp3,Mdha7]-MC-LR. While the adenylation domain comparison of McyAB between the two Planktothrix strains revealed considerable DNA recombination, the adenylation domain of McyC showed only a single amino acid substitution that was correlated with the replacement of Arg by Hty in position 4 of the microcystin molecule.

Abstract

Microcystins (MCs) are toxic heptapeptides found in cyanobacteria and share the common structure cyclo(-D-Ala1-L-X2-D-isoMeAsp3-L-Z4-Adda5-D-isoGlu6-Mdha7). The letters X and Z in the general formula above represent a wide range of L-amino acids that occupy positions 2 and 4, respectively. In general the variation in structural variants is due to the exchange of amino acids in position 7, 2, and 4. In the present work we report two homotyrosine (Hty)-containing microcystin variants, [D-Asp3,(E)-Dhb7]-MC-HtyY (1) and [D-Asp3,(E)-Dhb7]-MC-HtyHty (2), which were isolated from strain No80 of Planktothrix rubescens. Their structures were elucidated using amino acid analysis as well as 1D- and 2D NMR techniques. The adenylation domains of McyABC involved in amino acid activation in positions 7, 2, and 4 of the microcystin molecule, respectively, were compared with corresponding genes of Planktothrix strain CYA126/8 producing [D-Asp3,Mdha7]-MC-RR and [D-Asp3,Mdha7]-MC-LR. While the adenylation domain comparison of McyAB between the two Planktothrix strains revealed considerable DNA recombination, the adenylation domain of McyC showed only a single amino acid substitution that was correlated with the replacement of Arg by Hty in position 4 of the microcystin molecule.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Plant and Microbial Biology
Dewey Decimal Classification:580 Plants (Botany)
Language:English
Date:October 2008
Deposited On:19 Feb 2009 21:20
Last Modified:05 Apr 2016 13:03
Publisher:American Chemical Society
ISSN:0163-3864
Publisher DOI:https://doi.org/10.1021/np800397u
PubMed ID:18939865

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