Toxins 2016, 8(3), 76; https://doi.org/10.3390/toxins8030076
Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins
1
Department of Plant Physiology and Development, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland
2
Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland
3
Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland
4
Department of Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistokatu 6 A, Turku 20520, Finland
*
Author to whom correspondence should be addressed.
Academic Editor: Luis Botana
Received: 12 January 2016 / Revised: 29 February 2016 / Accepted: 7 March 2016 / Published: 16 March 2016
(This article belongs to the Collection Marine and Freshwater Toxins)
Abstract
Bacterial degradation of toxic microcystins produced by cyanobacteria is a common phenomenon. However, our understanding of the mechanisms of these processes is rudimentary. In this paper several novel discoveries regarding the action of the enzymes of the mlr cluster responsible for microcystin biodegradation are presented using recombinant proteins. In particular, the predicted active sites of the recombinant MlrB and MlrC were analyzed using functional enzymes and their inactive muteins. A new degradation intermediate, a hexapeptide derived from linearized microcystins by MlrC, was discovered. Furthermore, the involvement of MlrA and MlrB in further degradation of the hexapeptides was confirmed and a corrected biochemical pathway of microcystin biodegradation has been proposed. View Full-TextKeywords:
microcystin; biodegradation; recombinant enzymes; biochemical pathway
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Dziga, D.; Zielinska, G.; Wladyka, B.; Bochenska, O.; Maksylewicz, A.; Strzalka, W.; Meriluoto, J. Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins. Toxins 2016, 8, 76.
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