Figure 2: The secondary and tertiary structure of U m u D 2 and U m u D 2 . (a) Secondary structure comparison between the U m u D 2 NMR [44, 45] and crystal [46] structures. The 𝛼 helices are shown in red, and 𝛽 sheets are shown in blue. Relative deuterium incorporation of U m u D 2 at 30 sec labeling in HXMS experiments is shown, and the colors are based on the relative deuterium percentage scale shown [51]. (b) Comparison of the NMR [44, 45] and crystal [46] structures of U m u D 2 . The color of the 𝛼 helices and 𝛽 sheets is consistent with (a). The active site regions are boxed and shown in the insets. A model of full-length U m u D 2 is shown [52].