In
enzymes, protein residues themselves carry charges and produce
a preorganized local electric field (LEF). Such LEFs can be modified
by strategically mutating the charged and polar residues to create
a designed LEF (D-LEF) to project on the reaction axis to modulate
the reactivity of the enzyme. We investigated the enzymatic degradation
of polyethylene terephthalate (PET) using in silico engineering of
CYP450 enzymes, which possess D-LEFs. We show that PET degradation
can, in principle, be catalyzed using a CYP450 scaffold through oxidative
cleavage of the ester bond. The PET degradation occurs in two crucial
steps; the first step is the usual hydroxylation reaction initiated
by compound I (Cpd I), while the second step is the dealkylation of
the gem-hydroxy moiety, which is driven by the preorganized
LEF of the CYP450 enzyme. Using molecular-level analyses for three
different enzymes, we found that each of the three can efficiently
catalyze the HAT reaction. However, only CYP450GcoA performs an efficient
dealkylation reaction since it possesses the only scaffold among the
three enzymes that has preorganized LEF properly oriented for dealkylation.
We show that a strategic mutation based on the designed LEF along
the reaction axis and the binding site architecture can evolve the
enzyme for the PET degradation reaction. Our study further provides
a key lesson that intuiting the LEF of the enzyme in the direction
of the reaction axis could be crucial in selecting the most suitable
scaffold for the desired reaction.