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. Author manuscript; available in PMC: 2016 Sep 4.
Published in final edited form as: Science. 2016 Mar 4;351(6277):1090–1093. doi: 10.1126/science.aad6881

Fig. 3. As TSS changes, RNAP leading-edge position changes, but RNAP trailing-edge position does not change.

Fig. 3

(A) RNAP trailing-edge position (left; slope ~0) and RNAP leading-edge position (right; slope ~1) as a function of mean TSS for each of the 64 discriminator sequences (~16,000 templates analyzed for each discriminator).

(B) Interpretation: changes in TSS selection result from changes in DNA scrunching. Gray, RNAP; yellow, σ; blue, -10 element nucleotides; purple, discriminator nucleotides; i and i+1, NTP binding sites; red, Bpa and nucleotide crosslinked to Bpa; boxes, DNA nucleotides (nontemplate-strand nucleotides above template-strand nucleotides; nucleotides downstream of -10 element numbered). Scrunching is indicated by bulged-out nucleotides. Anti-scrunching is indicated by a “stretched” nucleotide-nucleotide linkage.