Figure 4

Sequence logos for E. coli K12. Sequence logos of the nucleotides between positions -20 and 2 of the genes with a spacer from 1 to 12 bps long. For each position, the sequence logo shows the amount of information content and the frequency of nucleotides. The blank positions mean there is no information content. Those with information content contain a stack of nucleotides. The size of the nucleotide character is proportional to its frequency at that position. Each sequence logo has an average ΔG° value ranging from -20 to 2 bps of the genes separated by each of the spacers analyzed. The higher the ΔG° value, the stronger the binding between the 16S rRNAs and the mRNAs. The drops in ΔG° values indicate where the 5'A of the 16S rRNA tail (3'-CCUCCA-5') can bind the SD sequence. These drops are before the regions with high frequencies of As and Gs.