Fig. 2: Structural changes in Uba6 accompany transitions from adenylate to thiolation-competent states.
a Comparison of Uba6 SCCH domain in the open (adenylation active) and closed (thioester bond formation active) conformations. The adenylation domains (which serve as the rigid body of Uba6) were superimposed and the SCCH domains are shown as cartoons with the catalytic cysteines shown as spheres. The degree of rotation between each SCCH domain conformational state is indicated. To provide a frame of reference, the relative position of the catalytic cysteine in the other SCCH domain conformational states is indicated with semitransparent yellow circles and labeled accordingly in each of the panels. Selected helices of the SCCH domain are labeled and their N- and C- termini are indicated by “nt” and “ct,” respectively. b, c Elements in the Uba6OPEN/Ub-AMP/InsP6 (b, Left, Middle) and Uba6CLOSED/Ub-AMP (c, Left, Middle) structures that undergo conformational changes during the transition from the adenylation to thiolation-competent states are shown as color-coded and labeled cartoons with the rest of the complex shown as surface representation. Overview of the Uba6OPEN/Ub-AMP/InsP6 (b, Right) and Uba6CLOSED/Ub-AMP (c, Right) active sites with residues that contact the adenylate intermediate shown as sticks. Hydrogen bonds are shown as dashed lines and selected water molecules are shown as red spheres.
