Linked Life Data

10715102

Source:http://linkedlifedata.com/resource/pubmed/id/10715102

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2000-4-14
pubmed:abstractText
The xanthophyll cycle is an enzymatic, reversible process through which the carotenoids violaxanthin, antheraxanthin, and zeaxanthin are interconverted in response to the need to balance light absorption with the capacity to use the energy to drive the reactions of photosynthesis. The cycle is thought to be one of the main avenues for safely dissipating excitation energy absorbed by plants in excess of that needed for photosynthesis. One of the key factors needed to elucidate the molecular mechanism by which the potentially damaging excess energy is dissipated is the energy of the lowest excited singlet (S(1)) state of the xanthophyll pigments. Absorption from the ground state (S(0)) to S(1) is forbidden by symmetry, making a determination of the S(1) state energies of these molecules by absorption spectroscopy very difficult. Fluorescence spectroscopy is potentially the most direct method for obtaining the S(1) state energies. However, because of problems with sample purity, low emission quantum yields, and detection sensitivity, fluorescence spectra from these molecules, until now, have never been reported. In this work these technical obstacles have been overcome, and S(1) --> S(0) fluorescence spectra of violaxanthin and zeaxanthin are presented. The energies of the S(1) states deduced from the fluorescence spectra are 14 880 +/- 90 cm(-)(1) for violaxanthin and 14 550 +/- 90 cm(-)(1) for zeaxanthin. The results provide important insights into the mechanism of nonphotochemical dissipation of excess energy in plants.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2831-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Mechanism of nonphotochemical quenching in green plants: energies of the lowest excited singlet states of violaxanthin and zeaxanthin.
pubmed:affiliation
Department of Chemistry, U-60, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, USA. frank@uconnvm.uconn.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't