Linked Life Data

8718624

Source:http://linkedlifedata.com/resource/pubmed/id/8718624

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1996-10-31
pubmed:abstractText
Carotenoids are C40 tetraterpenoids synthesized by nuclear-encoded multienzyme complexes located in the plastids of higher plants. To understand further the components and mechanisms involved in carotenoid synthesis, we screened Arabidopsis for mutations that disrupt this pathway and cause accumulation of biosynthetic intermediates. Here, we report the identification and characterization of two nonallelic albino mutations, pds1 and pds2 (for phytoene desaturation), that are disrupted in phytoene desaturation and as a result accumulate phytoene, the first C40 compound of the pathway. Surprisingly, neither mutation maps to the locus encoding the phytoene desaturase enzyme, indicating that the products of at least three loci are required for phytoene desaturation in higher plants. Because phytoene desaturase catalyzes an oxidation reaction, it has been suggested that components of an electron transport chain may be involved in this reaction. Analysis of pds1 and pds2 shows that both mutants are plastoquinone and tocopherol deficient, in addition to their inability to desaturate phytoene. Separate steps of the plastoquinone/tocopherol biosynthetic pathway are affected by these two mutations. The pds1 mutation affects the enzyme 4-hydroxyphenylpyruvate dioxygenase because it can be rescued by growth on the product but not the substrate of this enzyme, homogentisic acid and 4-hydroxyphenylpyruvate, respectively. The pds2 mutation most likely affects the prenyl/phytyl transferase enzyme of this pathway. Because tocopherol-deficient mutants in the green alga Scenedesmus obliquus can synthesize carotenoids, our findings demonstrate conclusively that plastoquinone is an essential component in carotenoid synthesis. We propose a model for carotenoid synthesis in photosynthetic tissue whereby plastoquinone acts as an intermediate electron carrier between carotenoid desaturases and the photosynthetic electron transport chain.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-11607209, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-13671378, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-1396714, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-1400305, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-2384084, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-2643695, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-3985624, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-6290210, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-7920709, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-8033911, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-8275101, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-8349618, http://linkedlifedata.com/resource/pubmed/commentcorrection/8718624-8382628
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1040-4651
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2139-49
pubmed:dateRevised
2010-9-13
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Genetic dissection of carotenoid synthesis in arabidopsis defines plastoquinone as an essential component of phytoene desaturation.
pubmed:affiliation
Department of Biochemistry, University of Arizona, Tucson 85721, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.