Microcystin-degrading bacteria first degrade microcystins by microcystinase A (MlrA) to cleave the cyclic structure of microcystins at the Adda-Arg site of microcystin-LR, microcystin-RR, and microcystin-YR, but the cleavage of the other microcystins was not clear. In our study, the microcystin-degrading bacterium Sphingopyxis sp. C-1 as wild type and that of mlrA-disrupting mutant, Sphingopyxis sp. CMS01 were used for microcystins biodegradation. The results showed MlrA degraded microcystin-LA, microcystin-LW, microcystin-LY, microcystin-LF, and nodularin. MlrA could cleave the Adda-L-amino acid site.

中文翻译：

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MlrA，微囊藻毒素和节球菌素在微囊藻毒素降解细菌中第一步生物降解的必需酶

微囊藻毒素降解菌首先通过微囊藻毒素酶A（MlrA）降解微囊藻毒素，在微囊藻毒素-LR、微囊藻毒素-RR、微囊藻毒素-YR的Adda-Arg位点裂解微囊藻毒素的环状结构，但对其他微囊藻毒素的裂解尚不清楚。在我们的研究中，微囊藻毒素降解细菌Sphingopyxis sp。C-1作为野生型，以及mlrA破坏突变体Sphingopyxis sp。CMS01 用于微囊藻毒素的生物降解。结果显示，MlrA 降解微囊藻毒素-LA、微囊藻毒素-LW、微囊藻毒素-LY、微囊藻毒素-LF 和结球菌素。MlrA 可以裂解 Adda-L-氨基酸位点。