Fig. 5: Proposed mechanisms for transcription initiation.
From: Structural basis of pausing during transcription initiation in mycobacterium tuberculosis
A,B σE factors facilitate RNAP in forming a transcription bubble and initiating the synthesis of short RNA transcripts in either (A) a post-translocation state or (B) a pre-translocation state. C. Rotation of the swivel module and σE factors induces a transcriptionally paused state. D–F Release of short RNA transcripts leads to abortive initiation (D), while dissociation of σE factors enables promoter escape and transition to an elongation state (E,F). RNAP core domain and swivel domain are in yellow and blue, respectively. BH is in blue (PIC) or bright orange (IC or EC). Other molecular colors are consistent with Fig. 1.
