Members of this family are essential for the interaction of the gp45 sliding clamp with the corresponding polymerase. They adopt a DNA clamp fold, consisting of two alpha helices and two beta sheets - the fold is duplicated and has internal pseudo two-fold symmetry [1].

1: Building a replisome from interacting pieces: sliding clamp complexed to a peptide from DNA polymerase and a polymerase editing complex. Shamoo Y, Steitz TA; Cell. 1999;99:155-166. PMID:10535734