Radical S-adenosyl methionine peptide epimerases (RSPEs) are an enzyme family that accomplishes regiospecific and irreversible introduction of multiple d-configured residues into ribosomally encoded peptides. Collectively, RSPEs can generate diverse epimerization patterns in a wide range of substrates. Previously, the lack of rapid methods to localize epimerized residues has impeded efforts to investigate the function and applicative potential of RSPEs. An efficient mass spectrometry-based assay is introduced that permits characterization of products generated in E. coli. Applying this to a range of non-natural peptide-epimerase combinations, it is shown that the d-amino acid pattern is largely but not exclusively dictated by the core peptide sequence, while the epimerization order is dependent on the enzyme-leader pair. RSPEs were found to be highly promiscuous, which allowed for modular introduction of peptide segments with defined patterns.
|Original language||English (US)|
|Number of pages||5|
|Journal||Angewandte Chemie - International Edition|
|State||Published - Jan 16 2017|
Bibliographical noteFunding Information:
We thank M. Helf for a sample of PoyH and MS annotation software, and S. Fuchs for insightful discussion. J.P. acknowledges funding from the SNF (31003A_146992/1) and EU (SYNPEPTIDE), B.I.M. is a fellowship recipient of the Alexander von Humboldt foundation. M.F.F. is recipient of a Human Frontier Science Program Long-term Fellowship.
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- peptide biosynthesis