Purification and Activity of the Second Recombinant Enzyme for Biodegrading Linearized Microcystins by Sphingopyxis sp. USTB-05

Abstract

Hepatotoxic microcystins (MCs) are produced and released by the harmful bloom-forming cyanobacteria, which severely threaten drinking water safety and human health due to their high toxicity, widespread distribution, and structural stability. The linearized microcystinase (MlrB) further hydrolyses the poisonous linearized MCs produced by the microcystinase-catalysed MCs to form tetrapeptides. Here, the purification and activity of MlrB were investigated. The results showed that the linearized products generated by 12.5 mg/L MC-LR and MC-RR were removed by purified recombinant MlrB at a protein concentration of 1 mg/L within 30 min. The high catalytic activity of MlrB can be obtained via heterologous expression and affinity purification, which lays the foundation for further studies on the properties and mechanism of MCs biodegradation enzymes.

Enzymatic mechanism of MlrB for catalyzing linearized microcystins by Sphingopyxis sp. USTB-05

“…Based on the analysis of the molecular docking binding pattern results, six mutants of MlrB were constructed using previous method ( Teng et al, 2023 ). After inducing the expression of the target protein, we conducted chromatography purification using affinity, concentrated the sample by ultrafiltration, and analyzed by SDS-PAGE.…”

“…The optimal purification scheme for pure MlrB has been obtained in previous studies ( Teng et al, 2023 ). Purified MlrB enzyme from Sphingopyxis sp.…”

“…USTB-05 was successfully obtained using recombinant Escherichia. coli ( E. coli ) overexpression and affinity purification in previous studies ( Xu et al, 2020 ; Teng et al, 2023 ). MlrB with low concentration was able to biodegrade linearized MCs within 30 min completely ( Teng et al, 2023 ).…”

“…coli ( E. coli ) overexpression and affinity purification in previous studies ( Xu et al, 2020 ; Teng et al, 2023 ). MlrB with low concentration was able to biodegrade linearized MCs within 30 min completely ( Teng et al, 2023 ). The functions of enzymes are related to their structural features.…”

<i>Morchella</i> Effectively Removes Microcystins Produced by <i>Microcystis aeruginosa</i>

“…Physical methods and chemical reactions do not offer economical or effective solutions for MC removal ( Li et al , 2017 ; Duan et al , 2018 ). In contrast, microbial methods are widely regarded for their cost-effectiveness, environmental friendliness, and ecological restoration capabilities ( Neilan et al , 2012 ; Dziga et al , 2013 ; Teng et al , 2023 ). However, most MC-degrading bacteria cannot completely eliminate MCs ( Massey and Yang, 2020 ; Zhan and Hong, 2022 ).…”