title: Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins.
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.
authors.affiliation: Department of Plant Physiology and Development, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. dariusz.dziga@uj.edu.pl.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Dziga
authors.affiliation: Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. gabriela.zielinska@uj.edu.pl.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Zielinska
authors.affiliation: Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. wladykab@interia.pl.
authors.forename: Benedykt
authors.initials: B
authors.lastname: Wladyka
authors.affiliation: Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. oliwia.bochenska@gmail.com.
authors.forename: Oliwia
authors.initials: O
authors.lastname: Bochenska
authors.affiliation: Department of Plant Physiology and Development, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. anna.maksylewicz@uj.edu.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Maksylewicz
authors.affiliation: Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Krakow 30387, Poland. wojciech.strzalka@uj.edu.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Strzalka
authors.affiliation: Department of Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistokatu 6 A, Turku 20520, Finland. jussi.meriluoto@abo.fi.
authors.forename: Jussi
authors.initials: J
authors.lastname: Meriluoto
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D052998:Microcystins / Q000378:metabolism*; D046931:Microcystis; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D052998:Microcystins; D011994:Recombinant Proteins
keywords: biochemical pathway; biodegradation; microcystin; recombinant enzymes