This domain is found at the C-terminal end of DNA polymerase III subunit alpha and similar proteins from Proteobacteria and Actinobacteria. This protein, which is the replicative DNA polymerase, consists of six domains that form an irregular pyramid around a central cavity. The C-terminal domain lies on top of this structure [1].

1: The structure of T. aquaticus DNA polymerase III is distinct from eukaryotic replicative DNA polymerases. Bailey S, Wing RA, Steitz TA; Cell. 2006;126:893-904. PMID:16959569

2: cryo-EM structures of the E. coli replicative DNA polymerase reveal its dynamic interactions with the DNA sliding clamp, exonuclease and tau. Fernandez-Leiro R, Conrad J, Scheres SH, Lamers MH; Elife. 2015; [Epub ahead of print] PMID:26499492