Linked Life Data

17253989

Source:http://linkedlifedata.com/resource/pubmed/id/17253989

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2007-2-23
pubmed:abstractText
Detoxification of xenobiotic compounds and heavy metals is a pivotal capacity of organisms, in which glutathione (GSH) plays an important role. In plants, electrophilic herbicides are conjugated to the thiol group of GSH, and heavy metal ions form complexes as thiolates with GSH-derived phytochelatins (PCs). In both detoxification processes of plants, phytochelatin synthase (PCS) emerges as a key player. The enzyme is activated by heavy metal ions and catalyzes PC formation from GSH by transferring glutamylcysteinyl residues (gamma-EC) onto GSH. In this study with Arabidopsis, we show that PCS plays a role in the plant-specific catabolism of glutathione conjugates (GS-conjugates). In contrast to animals, breakdown of GS-conjugates in plants can be initiated by cleavage of the carboxyterminal glycine residue that leads to the generation of the corresponding gamma-EC-conjugate. We used the xenobiotic bimane in order to follow GS-conjugate turnover. Functional knockout of the two PCS of Arabidopsis, AtPCS1 and AtPCS2, revealed that AtPCS1 provides a major activity responsible for conversion of the fluorescent bimane-GS-conjugate (GS-bimane) into gamma-EC-bimane. AtPCS1 deficiency resulted in a gamma-EC-bimane deficiency. Transfection of PCS-deficient cells with AtPCS1 recovered gamma-EC-bimane levels. The level of the gamma-EC-bimane conjugate was enhanced several-fold in the presence of Cd2+ ions in the wild type, but not in the PCS-deficient double mutant, consistent with a PCS-catalyzed GS-conjugate turnover. Thus AtPCS1 has two cellular functions: mediating both heavy metal tolerance and GS-conjugate degradation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
740-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Function of phytochelatin synthase in catabolism of glutathione-conjugates.
pubmed:affiliation
Lehrstuhl für Botanik, Technische Universtät München, D-85350 Freising, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't