title: The influence of phase transitions in phosphatidylethanolamine models on the activity of violaxanthin de-epoxidase.
abstract: In the present study, the influence of the phospholipid phase state on the activity of the xanthophyll cycle enzyme violaxanthin de-epoxidase (VDE) was analyzed using different phosphatidylethanolamine species as model lipids. By using (31)P NMR spectroscopy, differential scanning calorimetry and temperature dependent enzyme assays, VDE activity could directly be related to the lipid structures the protein is associated with. Our results show that the gel (L beta) to liquid-crystalline (L alpha) phase transition in these single lipid component systems strongly enhances both the solubilization of the xanthophyll cycle pigment violaxanthin in the membrane and the activity of the VDE. This phase transition has a significantly stronger impact on VDE activity than the transition from the L alpha to the inverted hexagonal (HII) phase. Especially at higher temperatures we found increased VDE reaction rates in the presence of the L alpha phase compared to those in the presence of HII phase forming lipids. Our data furthermore imply that the HII phase is better suited to maintain high VDE activities at lower temperatures.
authors.affiliation: Institute of Biology I, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany. vieler@rz.uni-leipzig.de <vieler@rz.uni-leipzig.de>
authors.forename: Astrid
authors.initials: A
authors.lastname: Vieler
authors.forename: Holger A
authors.initials: HA
authors.lastname: Scheidt
authors.forename: Peter
authors.initials: P
authors.lastname: Schmidt
authors.forename: Cindy
authors.initials: C
authors.lastname: Montag
authors.forename: Janine F
authors.initials: JF
authors.lastname: Nowoisky
authors.forename: Martin
authors.initials: M
authors.lastname: Lohr
authors.forename: Christian
authors.initials: C
authors.lastname: Wilhelm
authors.forename: Daniel
authors.initials: D
authors.lastname: Huster
authors.forename: Reimund
authors.initials: R
authors.lastname: Goss
mesh_terms: D050356:Lipid Metabolism; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D010088:Oxidoreductases / Q000378:metabolism*; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D012995:Solubility; D018724:Spinacia oleracea / Q000201:enzymology*; D013696:Temperature; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D010714:Phosphatidylethanolamines; D024341:Xanthophylls; C483858:phosphatidylethanolamine; C005613:violaxanthin; D010088:Oxidoreductases; C023290:violaxanthin de-epoxidase