This domain is found in the subunit RPC3 (also known as RPC62) of the eukaryotic DNA-directed RNA polymerase III, which synthesises small RNAs, such as 5S rRNA and tRNAs. RPC3 shows four defined domains folded around a fifth C-terminal domain consisting of two long alpha- helices (this entry). This domain appears to be reminiscent of coiled- coil motifs [1].

1: Structure-function analysis of hRPC62 provides insights into RNA polymerase III transcription initiation. Lefevre S, Dumay-Odelot H, El-Ayoubi L, Budd A, Legrand P, Pinaud N, Teichmann M, Fribourg S; Nat Struct Mol Biol. 2011;18:352-358. PMID:21358628