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. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Methods. 2008 Oct 21;47(1):37–43. doi: 10.1016/j.ymeth.2008.10.006

Fig. 3.

Fig. 3

SAM-dependent transcription termination of the S box riboswitch. (a) In vitro transcription of a B. subtilis yitJ template in the presence or absence of SAM. The template consists of the yitJ 5′ sequence (residues +14 to +289, relative to the yitJ transcription start-site) preceded by the constitutive B. subtilis glyQS promoter. Transcription by B. subtilis RNAP was initiated with ApC (corresponding to the +1/+2 positions of the transcript) in the presence of ATP, CTP and UTP to generate a halted TEC at +17. SAM was added as indicated (0-2.4 μM final concentration), and the products were resolved by 6% denaturing PAGE. Terminated (T, 185 nt, filled circles) and run-off (RO, 235 nt, open circles) RNAs are labeled. (b) Quantification of the SAM response. Termination efficiency is defined as the fraction of RNA at the terminator (T) relative to the total RNA (T + RO).