Complete reconstitution of the diverse pathways of gentamicin B biosynthesis.

Yeon Hee Ban, Myoung Chong Song, Jae-Yeon Hwang, Hea-Lyung Shin, Hak Joong Kim, Seung Kon Hong, Na Joon Lee, Je Won Park, Sun-Shin Cha, Hung-Wen Liu, Yeo Joon Yoon

Nature chemical biology 2019 Mar

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Gentamicin B (GB), a valuable starting material for the preparation of the semisynthetic aminoglycoside antibiotic isepamicin, is produced in trace amounts by the wild-type Micromonospora echinospora. Though the biosynthetic pathway to GB has remained obscure for decades, we have now identified three hidden pathways to GB production via seven hitherto unknown intermediates in M. echinospora. The narrow substrate specificity of a key glycosyltransferase and the C6'-amination enzymes, in combination with the weak and unsynchronized gene expression of the 2'-deamination enzymes, limits GB production in M. echinospora. The crystal structure of the aminotransferase involved in C6'-amination explains its substrate specificity. Some of the new intermediates displayed similar premature termination codon readthrough activity but with reduced toxicity compared to the natural aminoglycoside G418. This work not only led to the discovery of unknown biosynthetic routes to GB, but also demonstrated the potential to mine new aminoglycosides from nature for drug discovery.

Citation

Yeon Hee Ban, Myoung Chong Song, Jae-Yeon Hwang, Hea-Lyung Shin, Hak Joong Kim, Seung Kon Hong, Na Joon Lee, Je Won Park, Sun-Shin Cha, Hung-Wen Liu, Yeo Joon Yoon. Complete reconstitution of the diverse pathways of gentamicin B biosynthesis. Nature chemical biology. 2019 Mar;15(3):295-303