Structure of K. lactis Rna14–Rna15 complex. (A) Three Rna14 HAT domain dimers (in cyan, green, and yellow) related by a noncrystallographic threefold axis (red triangle). The complex between the C-terminal region of Rna14 and the hinge region of Rna15 (in orange, red, and blue) are located between the dimers. (B) Side view of the trimeric association of the HAT domain dimers. The complex is only found between the HAT domains at the top, while the equivalent position for the complex between the bottom HAT domains (indicated with the orange circle) is blocked by crystal packing. (C) Overlay of the crystal structure of the C-terminal region of K. lactis Rna14 (in red) in complex with the hinge region of Rna15 (in light green) with the solution structure of the S. cerevisiae complex (in gray) (Moreno-Morcillo et al. 2011). The first model of the NMR structure is used for this comparison. (D) Structure of the K. lactis Rna14 dimer in complex with Rna15 hinge domain (light green). The C-terminal region of Rna14 is shown in red. A semi-transparent molecular surface for the complex is also shown. (E) Two possible interpretations (I and II) for the locations of the complex relative to the HAT domain dimer. The connection between the HAT domain and the C-terminal region is indicated with the dashed lines (in orange). Residues in this linker are disordered in the structure. Panel D corresponds to the first arrangement. (F) A close-up view of the second arrangement for the complex relative to the HAT domain dimer. The position of the first arrangement is shown as a molecular surface. The view is related to that of panel E by a ∼180° rotation around the vertical axis.
