Fig. 2
Synonymous codon usage plays an important role in regulating gene expression. A Altered CcdB levels (ESCcdB) as a function of change in codon usage (RCU) relative to WT upon synonymous substitution. Mutants in N-terminal, middle and C-terminal regions are shown in blue, green and pink, respectively. B-C Left panel shows the corresponding values of ESCcdB (x-axis), ESRelE (y-axis) and RCU (color bar) for each mutant of the (B) N-terminal region and (C) C-terminal region. WT score is represented by black lines. Right panel shows the correlation between experimentally determined relative fitness values with various sequence-based parameters for the (B) N-terminal region and (C) C-terminal region. B-C The right panel shows the Pearson’s correlation coefficient values and their corresponding P values. Gradation of white to red colour reflects positive correlation whereas the gradation of white to blue color reflects negative correlation. Non-significant correlations, i.e., correlations with P > 0.05 are shown with a cross ‘X’ mark. Parameter definitions are in the Materials and Methods section