Development of Enzymatic Variants for the Synthesis of Bioresorbable Polyesters

Enzymatic synthesis of polymeric materials is a powerful approach to make these processes greener, more economical, and safer for scale-up. Herein, we characterized new variants of the hyperthermophilic carboxylesterase from the archaeon Archaeoglobus fulgidus with quantum mechanics/molecular mechanics molecular dynamics simulations. The designed variants were expressed and tested for the synthesis of poly­(ε-caprolactone) and triblock poly­(ε-caprolactone)–poly­(ethylene glycol), two important biomaterials. The reactant complexes of the best variants formed stronger hydrogen bonds with the nucleophilic oxygen and the subsequent tetrahedral intermediates formed stronger hydrogen bonds with the leaving lactone oxygen, reflecting the best active site preorganization for stabilization of the two consecutive transition states that involve the same active site machinery. Our findings set the underpinning ground to redesign other enzymes for polyesterification reactions.