InterPro domain: IPR044682

Violaxanthin de-epoxidase (VDE) is localised in the thylakoid lumen and catalyses the two-step mono de-epoxidation of violaxanthin to form antheraxanthin and zeaxanthin, to control the concentration of zeaxanthin in chloroplasts. It is part of a conserved system that dissipates excess energy as heat in the light-harvesting complexes of photosystem II (PSII) and protects them from photodamage [ 1 , 2 , 3 ]. The thylakoid lumen pH decreases under excessive light that allows VDE to attach to the thylakoid membrane where violaxanthin is located. This acidic condition causes the opening of the lipocalin barrel [ 4 ].

1. Overexpression of violaxanthin de-epoxidase: properties of C-terminal deletions on activity and pH-dependent lipid binding. Planta 214, 476-83
2. Photodamage of the photosynthetic apparatus and its dependence on the leaf developmental stage in the npq1 Arabidopsis mutant deficient in the xanthophyll cycle enzyme violaxanthin de-epoxidase. Plant Physiol 124, 273-84
3. Molecular cloning and characterization of violaxanthin de-epoxidase (CsVDE) in cucumber. PLoS One 8, e64383