FEBS Letters | |
Divergent evolution of flavonoid 2‐oxoglutarate‐dependent dioxygenases in parsley 1 | |
Martens, Stefan3  Lukačin, Richard3  Britsch, Lothar1  Matern, Ulrich3  Wellmann, Frank3  Forkmann, Gert2  | |
[1] Merck KgaA, Frankfurterstrasse 250, D-64271 Darmstadt, Germany;Technische Universität München, Wissenschaftszentrum für Ernährung, Landnutzung und Umwelt, Department für Pflanzenwissenschaften, Lehrstuhl für Zierpflanzenbau, Am Hochanger 4, D-85350 Freising, Germany;Institut für Pharmazeutische Biologie, Philipps-Universität Marburg, Deutschhausstrasse 17 A, D-35037 Marburg, Germany | |
关键词: Apiaceae; Flavonoid biosynthesis; 2-Oxoglutarate-dependent dioxygenase; Petroselinum crispum; ANS; anthocyanidin synthase; FNS; flavone synthase; FHT; flavanone 3β-hydroxylase; FLS; flavonol synthase; AP; apigenin; DHK; dihydrokaempferol; KM; kaempferol; NAR; naringenin; | |
DOI : 10.1016/S0014-5793(03)00479-4 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
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 FeII/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 3β-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 γ-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.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
---|---|---|---|
RO201912020313000ZK.pdf | 886KB | download |