Cysteine oxidation as a regulatory mechanism of Arabidopsis plastidial NAD-dependent malate dehydrogenase.
Physiol Plant
; 176(3): e14340, 2024.
Article
in En
| MEDLINE
| ID: mdl-38741259
ABSTRACT
Malate dehydrogenases (MDHs) catalyze a reversible NAD(P)-dependent-oxidoreductase reaction that plays an important role in central metabolism and redox homeostasis of plant cells. Recent studies suggest a moonlighting function of plastidial NAD-dependent MDH (plNAD-MDH; EC 1.1.1.37) in plastid biogenesis, independent of its enzyme activity. In this study, redox effects on activity and conformation of recombinant plNAD-MDH from Arabidopsis thaliana were investigated. We show that reduced plNAD-MDH is active while it is inhibited upon oxidation. Interestingly, the presence of its cofactors NAD+ and NADH could prevent oxidative inhibition of plNAD-MDH. In addition, a conformational change upon oxidation could be observed via non-reducing SDS-PAGE. Both effects, its inhibition and conformational change, were reversible by re-reduction. Further investigation of single cysteine substitutions and mass spectrometry revealed that oxidation of plNAD-MDH leads to oxidation of all four cysteine residues. However, cysteine oxidation of C129 leads to inhibition of plNAD-MDH activity and oxidation of C147 induces its conformational change. In contrast, oxidation of C190 and C333 does not affect plNAD-MDH activity or structure. Our results demonstrate that plNAD-MDH activity can be reversibly inhibited, but not inactivated, by cysteine oxidation and might be co-regulated by the availability of its cofactors in vivo.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxidation-Reduction
/
Arabidopsis
/
Cysteine
/
Malate Dehydrogenase
Language:
En
Journal:
Physiol Plant
Year:
2024
Document type:
Article
Affiliation country:
Alemania
Country of publication:
Dinamarca