The Genomic Pattern of tDNA Operon Expression in E. coli
Figure 4
Residuals of the Operon Model Regressions Used to Estimate Expression (Without Intercept), Showing Unexplained Variation
Only residuals with absolute values larger than 10−14 are shown. Thus, variation in all but nine of the 44 operons is completely explained. All operons containing tDNAs with these non-zero residuals are arrayed at the bottom, showing true tDNA order from 5′ to 3′. All such tDNAs are in single-copy except for the genes encoding Ala1B in the ribosomal operons, indicated by vertical stacking at the bottom, Arg3, which is repeated three times in the serV operon, and MetM, Gln1, and Gln2, which are each repeated twice in the metT operon (for its true configuration, see Table 1). Residuals are shown in μM units, those of standardized concentrations. Residuals are shown for each tDNA in order of increasing growth rate from 0.4 (leftmost) to 2.5 doublings/h (rightmost). Positive (negative) residuals indicate underestimation (overestimation) by the model.