Insights into the binding mechanism of ascorbic acid and violaxanthin with violaxanthin de-epoxidase (VDE) and chlorophycean violaxanthin de-epoxidase (CVDE) enzymes

© 2023. The Author(s), under exclusive licence to Springer Nature B.V..

Photosynthetic organisms have evolved to work under low and high lights in photoprotection, acting as a scavenger of reactive oxygen species. The light-dependent xanthophyll cycle involved in this process is performed by a key enzyme (present in the thylakoid lumen), Violaxanthin De-Epoxidase (VDE), in the presence of violaxanthin (Vio) and ascorbic acid substrates. Phylogenetically, VDE is found to be connected with an ancestral enzyme Chlorophycean Violaxanthin De-Epoxidase (CVDE), present in the green algae on the stromal side of the thylakoid membrane. However, the structure and functions of CVDE were not known. In search of functional similarities involving this cycle, the structure, binding conformation, stability, and interaction mechanism of CVDE are explored with the two substrates compared to VDE. The structure of CVDE was determined by homology modeling and validated. In silico docking (of first-principles optimized substrates) revealed it has a larger catalytic domain than VDE. A thorough analysis of the binding affinity and stability of four enzyme-substrate complexes is performed by computing free energies and their decomposition, the root-mean-square deviation (RMSD) and fluctuation (RMSF), the radius of gyration, salt bridge, and hydrogen bonding interactions in molecular dynamics. Based on these, violaxanthin interacts with CVDE to a similar extent as that of VDE. Hence, its role is expected to be the same for both enzymes. On the contrary, ascorbic acid has a weaker interaction with CVDE than VDE. Given these interactions drive epoxidation or de-epoxidation in the xanthophyll cycle, it immediately discerns that either ascorbic acid does not participate in de-epoxidation or a different cofactor is necessary as CVDE has a weaker interaction with ascorbic acid than VDE.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:156

Enthalten in:

Photosynthesis research - 156(2023), 3 vom: 27. Juni, Seite 337-354

Sprache:

Englisch

Beteiligte Personen:

Biswal, Satyaranjan [VerfasserIn]
Gupta, Parth Sarthi Sen [VerfasserIn]
Panda, Saroj Kumar [VerfasserIn]
Bhat, Haamid Rasool [VerfasserIn]
Rana, Malay Kumar [VerfasserIn]

Links:

Volltext

Themen:

51C926029A
CVDE
DFT
EC 1.-
Free energy
Journal Article
Molecular dynamics
Oxidoreductases
VDE
Violaxanthin
Violaxanthin de-epoxidase
Xanthophyll cycle
Xanthophylls

Anmerkungen:

Date Completed 24.05.2023

Date Revised 24.05.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1007/s11120-023-01006-0

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM353540137