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Figure 7
Experimental (kcat) and calculated activation free energies (ΔG‡) for the deprotonation of DHAP by diverse S. cerevisiae TIM variants. Effects of amino-acid substitutions with experimental data from TIM enzymes of different organisms (chicken and Trypanosoma brucei brucei) were also calculated for the yeast enzyme but, as expected, gave less agreement (see Supplementary Fig. S3), illustrating that mutational effects cannot be easily transferred between enzymes with only around 50% sequence identity. Note also that substitutions in the chicken enzyme shown in Supplementary Fig. S3 involve His95, which is catalytically relevant in the subsequent reaction step. The experimental kcat values were obtained at 25°C (Zhai et al., 2015BB99) and were used to estimate the ΔG‡ of the rate-limiting step. The corresponding data can be found in Supplementary Table S2.

IUCrJ
Volume 4| Part 1| January 2017| Pages 50-64
ISSN: 2052-2525
https://doi.org/10.1107/S2052252516018017