Fig. 5.

Homotrimeric HIRA(644–1017) exhibits structural homology with the homotrimeric replisome factor Ctf4/AND-1. a (Left) Superpositions of the HIRA(644–1017) monomer (green) onto Ctf4 (yellow) and AND-1 (blue) monomers. These superpositions with Ctf4 and AND-1 give RMSDs values of 3.9 and 4.1 Å for 197 and 204 Cα atoms, respectively. (Right) Superpositions of the HIRA(644–1017) trimer onto Ctf4 (RMSD = 4.6 Å with 620 Cα atoms) and AND-1 (RMSD = 4.2 Å with 629 Cα atoms) trimers. These superpositions were performed using the program SUPERPOSE in CCP4⁴⁹. b Scheme of the predicted secondary structures of human HIRA, yeast Ctf4, and its human counterpart AND-1. They exhibit similarities, with a β-strand domain involved in the homotrimerization of the proteins, an α-helical domain in the C-terminus, and a WD40-repeat region in the N-terminus. The amino acids W799–D800 found critical for HIRA homotrimerization are indicated