Linked Life Data

11301335

Source:http://linkedlifedata.com/resource/pubmed/id/11301335

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
2001-6-18
pubmed:abstractText
In higher plants, the de-epoxidation of violaxanthin (Vx) to antheraxanthin and zeaxanthin is required for the pH-dependent dissipation of excess light energy as heat and by that process plays an important role in the protection against photo-oxidative damage. The de-epoxidation reaction was investigated in an in vitro system using reconstituted light-harvesting complex II (LHCII) and a thylakoid raw extract enriched in the enzyme Vx de-epoxidase. Reconstitution of LHCII with varying carotenoids was performed to replace lutein and/or neoxanthin, which are bound to the native complex, by Vx. Recombinant LHCII containing either 2 lutein and 1 Vx or 1.6 Vx and 1.1 neoxanthin or 2.8 Vx per monomer were studied. Vx de-epoxidation was inducible for all complexes after the addition of Vx de-epoxidase but to different extents and with different kinetics in each complex. Analysis of the kinetics indicated that the three possible Vx binding sites have at least two, and perhaps three, specific rate constants for de-epoxidation. In particular, Vx bound to one of the two lutein binding sites of the native complex, most likely L1, was not at all or only at a slow rate convertible to Zx. In reisolated LHCII, newly formed Zx almost stoichiometrically replaced the transformed Vx, indicating that LHCII and Vx de-epoxidase stayed in close contact during the de-epoxidation reactions and that no release of carotenoids occurred.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22154-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
De-epoxidation of violaxanthin after reconstitution into different carotenoid binding sites of light-harvesting complex II.
pubmed:affiliation
Institut für Biochemie der Pflanzen, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany. pjahns@uni-duesseldorf.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't