Fig. 2.
Structure of the GLD-2–GLD-3 core complex. (A) The structure of GLD-2ΔI–GLD-3NT is shown in cartoon representation, colored as in the schematics in Fig. 1A. The N- and C-terminal residues and the α-helices of GLD-2 are indicated. Disordered regions are shown with dotted lines. The region deleted for crystallization (residues 813–846) resides in the disordered loop region between α-helices 7 and 8. In stick representations are the three active-site aspartic acids and the Glu875 residue identified in the C. elegans gld-2 mutant allele h292 (42). The chloride ion is shown as a black sphere. This and all structure figures were made with the PyMOL program (57). (B) Upper shows a cartoon representation of GLD-2ΔI–GLD-3NT, oriented with a 180° rotation around a vertical axis with respect to the view in A. The N- and C-terminal residues and the α-helices of GLD-3 are labeled. The α6-α7 and α7-α8 insertions of the central domain are highlighted in black and gray, respectively. Center and Lower show the structures of Cid1 [PDB ID code 4E80 (39); UTP molecule shown as stick representation] and Trf4-Air2 [PDB ID code 3NYB (37); Air2 in yellow, Zn ions shown as gray spheres] with the same color coding and in the same orientation as GLD-2ΔI–GLD-3NT in Upper, after optimal superposition. N- and C-terminal residues are labeled. Disordered loop regions are highlighted with dotted lines.