Structural basis of RNA polymerase inhibition by viral and host factors

Abstract RNA polymerase inhibition plays an important role in the regulation of transcription response to environmental changes and virus-host relationship. Here we present high-resolution structures two such RNAP-inhibitor complexes that provide structural bases underlying RNAP archaea. The Acidianus two-tailed virus encodes RIP factor binds inside DNA-binding channel RNAP, inhibiting by occlusion binding sites for nucleic acid initiation TFB. Infection with Sulfolobus Turreted Icosahedral Virus induces expression host TFS4, which funnel similarly eukaryotic transcript cleavage factors. However, TFS4 allosterically a widening disrupts trigger loop bridge helix motifs. Importantly, conformational induced are closely related inactivated states other domains life indicating deep evolutionary conservation allosteric inhibition.