Figure 6. UIM-induced conformational dynamics in ubiquitin.

The sites that participate in conformational exchange processes are shown on the structure of the fusion protein. Interactions with the UIM induce conformational motions on the docking interface residues in addition to a second coordination layer of atoms and distal sites located in the extended loop that connects strands 3 and 4. Sites are color-coded according to the exchange process they participate in. Red: Process a – reorganization of the interface; Blue: Process b – induced loop motions; Magenta – undecided. The sidechains of Lysines at positions 6 and 48 that are confirmed ubiquitylation sites ⁴⁰ are also shown. Raw relaxation data for a selection of these sites is shown in Figure 5 while fit parameters in table 2.