title: Enzymatic pathway for biodegrading microcystin LR in Sphingopyxis sp. C-1.
abstract: The mlr gene cluster consisting of mlrA, mlrB, mlrC, and mlrD is involved in the degradation of the cyanobacterial toxin microcystin. However, it is unclear which degradation intermediates are metabolized by MlrB and MlrC. To address these questions, we constructed recombinant Escherichia coli to overproduce MlrB and MlrC from Sphingopyxis sp. C-1, and determined which intermediates were degraded in cell-free extracts. The cell-free extract containing MlrB degraded linearized microcystin-LR, giving rise to a tetrapeptide. The cell-free extract of MlrC degraded linearized microcystin-LR and also degraded the tetrapeptide to the amino acid Adda. These results indicate that linearized microcystin-LR is degraded by both MlrB and MlrC, and tetrapeptide is degraded by specifically by MlrC in Sphingopyxis sp. C-1.
authors.affiliation: Faculty of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura, Ora-gun, Gunma 374-0193, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Shimizu
authors.forename: Hideaki
authors.initials: H
authors.lastname: Maseda
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Okano
authors.forename: Takumi
authors.initials: T
authors.lastname: Kurashima
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kawauchi
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xue
authors.forename: Motoo
authors.initials: M
authors.lastname: Utsumi
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Zhang
authors.forename: Norio
authors.initials: N
authors.lastname: Sugiura
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D000087522:Cyanobacteria Toxins; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D008387:Marine Toxins / Q000737:chemistry / Q000378:metabolism*; D052998:Microcystins / Q000737:chemistry / Q000378:metabolism*; D005810:Multigene Family / Q000235:genetics; D059748:Proteolysis; D042301:Sphingomonadaceae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; C057862:cyanoginosin LR