Impact of the T296S mutation in P450 GcoA for aryl-O-demethylation: a QM/MM study

Autor: Sonia F. G. Santos, Rajesh Reddy Bommareddy, Gary W. Black, Warispreet Singh
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Frontiers in Chemistry, Vol 11 (2024)
Druh dokumentu: article
ISSN: 2296-2646
DOI: 10.3389/fchem.2023.1327398
Popis: Lignin, a complex plant cell wall component, holds promise as a renewable aromatic carbon feedstock. p-Vanillin is a key product of lignin depolymerization and a precursor of protocatechuic acid (PCA) that has tremendous potential for biofuel production. While the GcoAB enzyme, native to Amycolatopsis sp., naturally catalyzes aryl-O-demethylation toward guaiacol, recent research introduced a single mutation, T296S, into the GcoAP450 enzyme, enabling it to catalyze aryl-O-demethylation of p-vanillin. This structural modification increases the efficiency of GcoAP450 for the natural substrate while being active for p-vanillin. This study reveals the increased flexibility of p-vanillin and its ability to adapt a favorable conformation by aligning the methoxy group in close proximity to Fe(IV) = O of Cpd I in the active site of the T296S variant. The QM/MM calculations in accordance with the experimental data validated that the rate-limiting step for the oxidation of p-vanillin is hydrogen atom abstraction and provided a detailed geometric structure of stationary and saddle points for the oxidation of p-vanillin.
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