Further characterization of glycine-containing microcystins from the McMurdo dry Valleys of Antarctica..pdf
Published version, 811.3Kb
Puddick, J., Prinsep, M. R., Wood, S. A., Cary, S. C., Hamilton, D. P., & Holland, P. T. (2015). Further characterization of glycine-containing microcystins from the McMurdo Dry Valleys of Antarctica. Toxins, 7(2), 493–515. http://doi.org/10.3390/toxins7020493
Permanent Research Commons link: http://hdl.handle.net/10289/9328
Microcystins are hepatotoxic cyclic peptides produced by several cyanobacterial genera worldwide. In 2008, our research group identified eight new glycine-containing microcystin congeners in two hydro-terrestrial mat samples from the McMurdo Dry Valleys of Eastern Antarctica. During the present study, high-resolution mass spectrometry, amino acid analysis and micro-scale thiol derivatization were used to further elucidate their structures. The Antarctic microcystin congeners contained the rare substitution of the position-1 D-alanine for glycine, as well as the acetyl desmethyl modification of the position-5 Adda moiety (3S-amino-9S-methoxy-2S,6,8S-trimethyl-10-phenyldeca-4E,6E-dienoic acid). Amino acid analysis was used to determine the stereochemistry of several of the amino acids and conclusively demonstrated the presence of glycine in the microcystins. A recently developed thiol derivatization technique showed that each microcystin contained dehydrobutyrine in position-7 instead of the commonly observed N-methyl dehydroalanine.
© 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).