Linked Life Data

12782296

Source:http://linkedlifedata.com/resource/pubmed/id/12782296

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-3
pubmed:dateCreated
2003-6-3
pubmed:databankReference
pubmed:abstractText
Flavone synthases (FNSs) catalyze the oxidation of flavanones to flavones, i.e. the formation of apigenin from (2S)-naringenin. While many plants express a microsomal-type FNS II, the soluble FNS I appears to be confined to a few species of the Apiaceae and was cloned recently from parsley plants. FNS I belongs to the Fe(II)/2-oxoglutarate-dependent dioxygenases characterized by short conserved sequence elements for cofactor binding, and its evolutionary context and mode of action are under investigation. Using a homology-based reverse transcription polymerase chain reaction approach, two additional flavonoid-specific dioxygenases were cloned from immature parsley leaflets, which were identified as flavanone 3beta-hydroxylase (FHT) and flavonol synthase (FLS) after expression in yeast cells. Sequence alignments revealed marginal differences among the parsley FNS I and FHT polypeptides of only 6%, while much less identity (about 29%) was observed with the parsley FLS. Analogous to FNS I, FLS oxidizes the flavonoid gamma-pyrone by introducing a C2, C3 double bond, and (2R,3S)-dihydrokaempferol (cis-dihydrokaempferol) was proposed recently as the most likely intermediate in both FNS I and FLS catalysis. Incubation of either FNS I or FLS with cis-dihydrokaempferol exclusively produced kaempferol and confirmed the assumption that flavonol formation occurs via hydroxylation at C3 followed by dehydratation. However, the lack of apigenin in these incubations ruled out cis-dihydrokaempferol as a free intermediate in FNS I catalysis. Furthermore, neither (+)-trans-dihydrokaempferol nor unnatural (-)-trans-dihydrokaempferol and 2-hydroxynaringenin served as a substrate for FNS I. Overall, the data suggest that FNS I has evolved uniquely in some Apiaceae as a paraphyletic gene from FHT, irrespective of the fact that FNS I and FLS catalyze equivalent desaturation reactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
544
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
93-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12782296-Amino Acid Sequence, pubmed-meshheading:12782296-Chromatography, Thin Layer, pubmed-meshheading:12782296-Cloning, Molecular, pubmed-meshheading:12782296-DNA, Complementary, pubmed-meshheading:12782296-Evolution, Molecular, pubmed-meshheading:12782296-Models, Chemical, pubmed-meshheading:12782296-Molecular Sequence Data, pubmed-meshheading:12782296-Oxidoreductases, pubmed-meshheading:12782296-Oxygen, pubmed-meshheading:12782296-Peptides, pubmed-meshheading:12782296-Petroselinum, pubmed-meshheading:12782296-Phylogeny, pubmed-meshheading:12782296-Plant Proteins, pubmed-meshheading:12782296-Polymerase Chain Reaction, pubmed-meshheading:12782296-Recombinant Proteins, pubmed-meshheading:12782296-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:12782296-Sequence Homology, Amino Acid, pubmed-meshheading:12782296-Substrate Specificity
pubmed:year
2003
pubmed:articleTitle
Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley.
pubmed:affiliation
Institut für Pharmazeutische Biologie, Philipps-Universität Marburg, Deutschhausstrasse 17 A, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't