Chemical Science
Edge Article
domains typical for PEP synthases and PPDKs but has no Additionally, both enzymes have potential as exible bio-
signicant sequence similarity to TalE (<20% on AA level). It catalysts for in vivo and in vitro engineering of bioactive small-
appears that members of this family of kinase enzymes have molecules.
evolved separately in bacteria to synthesize small-molecule
phosphoramidates in the primary and secondary metabolism.
It is tempting to speculate that putative PPDK homologs enco-
Conflicts of interest
ded in the BGCs for agrocin 84 and phaseolotoxin might have There are no conicts to declare.
an analogous role in the respective pathways.14,16
Acknowledgements
In vitro biosynthesis of phosphoramidon
We gratefully thank Hamada Saad for helpful advises, Dr Dor-
othee Wistuba for HR-MS support and Anika Winkler for expert
assistance during DNA sequencing. This work was generously
supported by the DFG (KA 3071/4-1 and GRK 1708). A. K. was
We next aimed to establish 5 as a genuine intermediate in the
biosynthesis of 1. Therefore, we added dTDP-L-rhamnose and
a TalC-containing protein extract to the TalE assay. Aer incu-
bation for 16 h at 30 ꢁC we analyzed the reaction mixture by LC-
supported by grants from the SFB 766.
MS and identied a single product peak matching 1 in retention
time, UV spectrum, mass and MS/MS fragmentation (Fig. 4, S1,
S6 and 7†). 1 was not produced when either 5, dTDP-L-rhamnose
Notes and references
or TalC were absent in the assay. These results show that TalC
uses 5 as an acceptor substrate to catalyze the transfer of
a deoxysugar to the phosphoryl group. In general, glycosylation
is a common theme in natural product biosynthesis altering
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Conclusions
In conclusion, we have identied the gene cluster for the
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exceptional biochemistry. An ATP-grasp amide ligase, a phos-
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a phosporamidate bridge. A preliminary search in public
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Chem. Sci.
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