This is a hybrid domain found in DNA-directed RNA polymerase subunit beta' (RPOC) found in Deinococcus [1-5].

1: Crystal structure of a bacterial RNA polymerase holoenzyme at 2.6 A resolution. Vassylyev DG, Sekine S, Laptenko O, Lee J, Vassylyeva MN, Borukhov S, Yokoyama S; Nature. 2002;417:712-719. PMID:12000971

2: Structural basis of transcription initiation: RNA polymerase holoenzyme at 4 A resolution. Murakami KS, Masuda S, Darst SA; Science. 2002;296:1280-1284. PMID:12016306

3: Structure and function of lineage-specific sequence insertions in the bacterial RNA polymerase beta' subunit. Chlenov M, Masuda S, Murakami KS, Nikiforov V, Darst SA, Mustaev A; J Mol Biol. 2005;353:138-154. PMID:16154587

4: Inhibition of bacterial RNA polymerase by streptolydigin: stabilization of a straight-bridge-helix active-center conformation. Tuske S, Sarafianos SG, Wang X, Hudson B, Sineva E, Mukhopadhyay J, Birktoft JJ, Leroy O, Ismail S, Clark AD Jr, Dharia C, Napoli A, Laptenko O, Lee J, Borukhov S, Ebright RH, Arnold E; Cell. 2005;122:541-552. PMID:16122422

5: Structural basis of transcriptional pausing in bacteria. Weixlbaumer A, Leon K, Landick R, Darst SA; Cell. 2013;152:431-441. PMID:23374340