TUNING CYSTEINE REACTIVITY AND SULFENIC ACID STABILITY BY PROTEIN MICROENVIRONMENT IN GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASES OF ARABIDOPSIS THALIANA

Cysteines and H2O2 are fundamental players in redox signaling. Cysteine-thiol deprotonation favors the reaction with H2O2 that generates sulfenic acids with dual electrophilic/nucleophilic nature. The protein microenvironment surrounding the target cysteine is believed to control whether a sulfenic acid can be reversibly regulated by disulfide formation or irreversibly oxidized to sulfinates/sulfonates. Here, we present experimental oxidation kinetics and a QM/MM investigation to elucidate the reaction of H2O2 with glycolytic (AtGAPC1) and photosynthetic glyceraldehyde-3-phosphate dehydrogenase (AtGAPA) from Arabidopsis thaliana.