Figure 1

Influence of protein biosynthetic rates on positional pathway regulation.(A) Regulatory efforts (r e g _i ) at different pathway positions for constrained protein biosynthetic rates. A low value of m corresponds to slow protein biosynthesis while a high value corresponds to fast protein biosynthesis. Medians are indicated by circles. Complete boxplots are shown in Additional file 1: Figure S4. (B) The regulatory effort, measured as average relative lengths of promoter regions at different pathway positions has been determined for organisms with slow and fast protein synthesis rates. At the initial step of pathways the regulatory effort is increased for organisms with slow protein synthesis whereas it is increased at the terminal position for organisms with fast protein synthesis. Average promoter length for organisms with slow protein synthesis is depicted in black (154 organisms) and grey is used for 155 organisms with fast protein synthesis. (C) Relative average promoter lengths in selected pathways for organisms with slow and fast protein biosynthesic rates. The medians of relative average promoter length for tryptophan biosynthesis (upper panel, data from 83 organisms) and uroporphyrinogen-III biosynthesis (an intermediate of heme biosynthesis, lower panel, data from 114 organisms) are shown. Data is shown for the initial and terminal reactions. Protein names correspond to those of the catalytic pathway in E. coli. Abbreviations: Initial R., initial reaction; Terminal R., terminal reaction; Chor, Chorismate; Trp, L-Tryptophan; Uro-III, uroporphyrinogen-III; Pheme IX, protoheme IX.