Figure 7.
Atomic force microscopy mechanochemistry experiments on the reduction of disulfide groups catalysed by thioredoxin. (a) Rates of disulfide reduction determined at low and high applied force for several thioredoxins from bacterial (blue) and eukaryotic (red) origin. The plot also includes data (green) for 23 variants of E. coli thioredoxin, taken from a combinatorial library of conservative mutations derived from statistical analyses of the sequence alignment. These variants span the range from bacterial thioredoxin to eukaryotic thioredoxin behaviour, thus suggesting the existence of multiple evolutionary paths between the two regimes. (b) Plots of reduction rate versus applied force for E. coli thioredoxin and one of its variants (trx*). This variant includes eight mutations and shows clear eukaryotic behaviour, with a depressed contribution of the chemical SN2 mechanism prevalent in bacterial thioredoxins. This research was originally published in [133]. © The Biochemical Society.