Figure 5. Complex PTMs.

The chemistry of those PTMs below the double line in Table 1, which exhibit potentially unlimited numbers of modifications, is summarised, as in Figure 4. The human ubiquitin sequence was obtained from PDB 1UBI, along with the secondary structure assignment through DSSP. The PDB entries of the ubiquitin structures are 1UBI for the monomer, 1AAR for the Lys48 dimer and 2JF5 for the Lys63 dimer. The structures were oriented and annotated in Open Source PyMol 1.2.X.