Figure 6. The TG dinucleotide, the −35 sequence and the spacer sequence of gapA P1 promoter are required for RPo formation.

RPos were formed with the commercial Eσ⁷⁰ RNAP and the supercoiled plasmid pRLG::gapAP1 carrying the WT promoter or with the pRLG::gapAP1 derivatives containing the gapA P1 promoter variant, under conditions described in the Experimental section. RPos were treated with KMnO₄ and analysed by primer extension with oligonucleotide 2559 (5′-ACCATCGGCGCTACGGCG-3′) under conditions described in Figure 2. A control elongation was performed without chemical treatment (lane 1). Nucleotides with an enhanced reactivity in the RPo are indicated on the right side of the autoradiogram.