%0 Journal Article
%T A native chemical ligation handle that enables the synthesis of advanced activity-based probes: diubiquitin as a case study.
%A Mulder MP
%A El Oualid F
%A ter Beek J
%A Ovaa H
%J Chembiochem
%V 15
%N 7
%D May 2014 5
%M 24623714
%F 3.461
%R 10.1002/cbic.201402012
%X We present the development of a native chemical ligation handle that also functions as a masked electrophile that can be liberated during synthesis when required. This handle can thus be used for the synthesis of complex activity-based probes. We describe the use of this handle in the generation of linkage-specific activity-based deubiquitylating enzyme probes that contain substrate context and closely mimic the native ubiquitin isopeptide linkage. We have generated activity-based probes based on all seven isopeptide-linked diubiquitin topoisomers and demonstrated their structural integrity and ability to label DUBs in a linkage-specific manner.