Delineating the biosynthesis of gentamicin X2, the common precursor of the gentamicin C antibiotic complex.
Chemistry and Biology
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Huang, C., Huang, F., Moison, E., Guo, J., Jian, X., Duan, X., Deng, Z., et al. (2015). Delineating the biosynthesis of gentamicin X2, the common precursor of the gentamicin C antibiotic complex.. Chemistry and Biology, 251-261. https://doi.org/10.1016/j.chembiol.2014.12.012
Gentamicin C complex is a mixture of aminoglycoside antibiotics used worldwide to treat severe Gramnegative bacterial infections. Despite its clinical importance, the enzymology of its biosynthetic pathway has remained obscure. We report here insights into the four enzyme-catalyzed steps that lead from the first-formed pseudotrisaccharide gentamicin A2 to gentamicin X2, the last common intermediate for all components of the C complex. We have used both targeted mutations of individual genes and reconstitution of portions of the pathway in vitro to show that the secondary alcohol function at C-3" of A2 is first converted to an amine, catalyzed by the tandem operation of oxidoreductase GenD2 and transaminase GenS2. The amine is then specifically methylated by the S-adenosyl-L-methionine (SAM)- dependent N-methyltransferase GenN to form gentamicin A. Finally, C-methylation at C-4" to form gentamicin X2 is catalyzed by the radical SAM-dependent and cobalamin-dependent enzyme GenD1.
This work was supported by a project grant from the Medical Research Council, UK (G1001687) to P.F.L.; and by the 973 and 863 programs from the Ministry of Science and Technology of China, National Science Foundation of China, and the Translational Medical Research Fund of Wuhan University School of Medicine to Y.S.; E.M. thanks the Gates Cambridge Trust for a scholarship. We also gratefully acknowledge Dr. Xinzhou Yang, SouthCentral University for Nationalities, for his assistance in separation of gentamicin A2. We thank Dr. Andrew Truman (John Innes Institute) for helpful discussions.
Medical Research Council (MR/M019020/1)
External DOI: https://doi.org/10.1016/j.chembiol.2014.12.012
This record's URL: https://www.repository.cam.ac.uk/handle/1810/246943
Attribution 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by/2.0/uk/
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