Plant cysteine oxidases are dioxygenases that directly enable arginyl transferase-catalysed arginylation of N-end rule targets.

Petra Majovsky, Domenika Thieme and Wolfgang Hoehenwarter from the Proteomics Unit of the Leibniz Institute of Plant Biochemistry (IPB), Halle, are acknowledged for MS of recombinant ATE1. David Staunton from the Biophysical Facility, Department of Biochemistry, University of Oxford, is acknowledged for multi-angle light scatter analysis of PCO1/4. Geoff Grime from the University of Surrey Ion Beam Centre is acknowledged for assistance with the microPIXE data collection. This work was supported by a Biotechnology and Biological Sciences Research Council (U.K.) New Investigator grant (BB/M024458/1) to E.F., a grant for setting up the junior research group of the ScienceCampus Halle–Plant-based Bioeconomy to N.D., by a PhD fellowship of the Landesgraduiertenförderung Sachsen-Anhalt awarded to C.N., by an Engineering and Physical Sciences Research Council (U.K.) studentship (EP/G03706X/1) to J.C.B.-B., a Royal Society Dorothy Hodgkin Fellowship to E.F., a William R. Miller Junior Research Fellowship (St Edmund Hall, Oxford) to R.J.H. and grant DI 1794/3-1 by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to N.D. Financial support came from the Leibniz Association, the state of Saxony Anhalt, the Deutsche Forschungsgemeinschaft (DFG) Graduate Training Center GRK1026 ‘Conformational Transitions in Macromolecular Interactions’ at Halle, and the Leibniz Institute of Plant Biochemistry (IPB) at Halle, Germany. We thank Professor J. van Dongen (RWTH Aachen University, Germany) and Professor F. Licausi (Scuolo Superiore Sant’Anna, Pisa, Italy) for sharing pDEST-PCO plasmids and helpful discussions. The manuscript was deposited as pre-print before publication (https://doi.org/10.1101/069336) at bioRxiv—the preprint server for biology, operated by Cold Spring Harbor Laboratory (biorxiv.org). Publication of this article was funded by the Open Access fund of the Leibniz Institute of Plant Biochemistry (IPB). This work was supported by the network