Fig. 5.

Sequences downstream of the pause are required for entry into the paused state. In vitro transcription of derivatives of DNA templates containing either the full-length WT mgtA leader or derivatives with the GCCTG sequence from +219 to +223 mutated to CGGAC, or with a single G-to-C substitution at position 219. Transcripts were analyzed 0.5, 1, 2, 3, 5, 7, 10, and 45 min after addition of all four NTPs to EC26. Arrows indicate positions of the Mg²⁺-sensitive pause at T218 and of the read-through transcript. The efficiency of the pause at position T218 is shown for each condition, together with the pause half-life for the WT template. n/a, not applicable.