Diagram of the NEDD8 linkages, as determined by mass spectrometry analysis, from (1E), with the number of spectral counts indicated for the bands labelled in (1E). Only bands with identified diGly motifs are shown here. UBE2M generates in vitro chains of poly-NEDD8 with linkages on K4, K6, K11, K22, K27, K48, K54, and K60. 