Fig. 2 |. Structure and cryo-EM density for selected regions of catalytic and regulatory modules and CysBD.
a, Well resolved density for the pol and exo active sites, including ligands, metal ions and water. Active sites in Polδ are configured as in the isolated catalytic module. (PDB 3IAY). b, Clear density for the regulatory module enabled modeling of regions that are not resolved in the human homolog (PDB 3E0J). c, Ab initio structure of 4Fe-4S cluster bound CysBD. Some side chains have been omitted for clarity. d, Sequence alignment of a section of CysBD spanning the conserved Arg1080.