This domain is found in some NusG proteins where it forms domain II [1]. However most NusG proteins are missing this domain. In other cases this domain is found in isolation [2]. The function of this domain is unknown.

1: Crystal structures of transcription factor NusG in light of its nucleic acid- and protein-binding activities. Steiner T, Kaiser JT, Marinkovic S, Huber R, Wahl MC; EMBO J. 2002;21:4641-4653. PMID:12198166

2: Solution NMR structure of Lin0431 protein from Listeria innocua reveals high structural similarity with domain II of bacterial transcription antitermination protein NusG. Tang Y, Xiao R, Ciccosanti C, Janjua H, Lee DY, Everett JK, Swapna GV, Acton TB, Rost B, Montelione GT; Proteins. 2010;78:2563-2568. PMID:20602357