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. 2021 Mar 3;49(6):3109–3126. doi: 10.1093/nar/gkab130

Figure 4.

Figure 4.

Quantitative analysis of the CTD binding affinity to the GTase. MMGBSA calculations (see details in the Methods) were performed on three replicates of the simulations containing the 4-heptad pSer5 CTD extended in the N-ter direction (System 6). (A) Per-residue decomposition analysis of the binding free energy. The key GTase residues that contribute to CTD binding are labelled and coloured according to the CDS site they belong to (see the plot legend box). The residues making significant contributions (below –2.1 kcal/mol) are all confined to the region between residues 320 and 440. (B) Comparison of the binding free energy between the wild-type GTase and the three mutants, where the positively charged residues of CDS1, CDS2 and both sites were mutated to alanine. The data is min-max normalized relative to the lowest value over all the conditions and the average for the WT + pSer5 condition. The result for the wild-type GTase with unphosphorylated CTD is also shown for comparison. Error bars denote one standard deviation. ANOVA followed by post-hoc Tukey tests were performed to calculate statistical significance between the mutants and the wild-type GTase + pSer5 CTD condition. * indicates that the differences are significant at P< 0.05, ** indicates that the differences are significant at P< 0.01, *** indicates that the differences are significant at P< 0.001, and NS indicates that the differences are not significant.