From outside ! Dr (α) Jekyl and Mister (β) Hyde. NusG homologs regulate transcription and coupled processes in all living organisms. The Escherichia coli (E. coli) two-domain paralogs NusG and RfaH have been shown in a recent Cell paper to bear identical N-terminal domains (NTDs) but dramatically different carboxy-terminal domains (CTDs), a β barrel in NusG and an α hairpin in RfaH.
The basal mechanism described in this paper affects a wide range of species, and has been tested by extensive analysis of global high-throughput expression data.Altogether, these results confirm and provide a quantitative framework for the long-proposed notion that the discriminator sequence is a significant determinant of promoter supercoiling sensitivity.