Dataset Information

Structure prediction of dihydroflavonol 4- reductase and anthocyanidin synthase from spinach.

ABSTRACT: Spinach is an important dietary vegetable associated with beneficial health effects. Flavonoids have various biological activities such as antioxidant, antibacterial, and anticancer effect Flavonoid including anthocyanin provides brilliant and colored pigments in different plant tissues. Anthocyanidin synthase and dihydroflavonol 4-reductase are responsible for anthocyanin biosynthesis. They contributed in plant protection against UV-B radiation, microbial and herbivore pathogens. A 3D structures of anthocyanidin synthase and dihydroflavonol 4-reductase from spinach are constructed in this study through homology modeling. The homology modeling is done by using the MODELLER 9v7 software. The energy of models was minimized by applying molecular mechanics method. The root mean square deviation (RMSD) for C atoms between the template and the homology-modeled structures was estimated by CE program. The final models were assessed by PROCHECK and WHATCHECK which showed that the final refined models are reliable.

SUBMITTER: Sahay A

PROVIDER: S-EPMC3055707 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Structure prediction of dihydroflavonol 4- reductase and anthocyanidin synthase from spinach.

Sahay Archna A Shakya Madhvi M

Bioinformation 20101127 6

Spinach is an important dietary vegetable associated with beneficial health effects. Flavonoids have various biological activities such as antioxidant, antibacterial, and anticancer effect Flavonoid including anthocyanin provides brilliant and colored pigments in different plant tissues. Anthocyanidin synthase and dihydroflavonol 4-reductase are responsible for anthocyanin biosynthesis. They contributed in plant protection against UV-B radiation, microbial and herbivore pathogens. A 3D structure ...[more]

PMID: 21364828

Similar Datasets

Project description:Grape hyacinth (Muscari spp.) is a popular ornamental plant with bulbous flowers noted for their rich blue color. Muscari species have been thought to accumulate delphinidin and cyanidin rather than pelargonidin-type anthocyanins because their dihydroflavonol 4-reductase (DFR) does not efficiently reduce dihydrokaempferol. In our study, we clone a novel DFR gene from blue flowers of Muscari. aucheri. Quantitative real-time PCR (qRT-PCR) and anthocyanin analysis showed that the expression pattern of MaDFR had strong correlations with the accumulation of delphinidin, relatively weak correlations with cyanidin, and no correations with pelargonidin. However, in vitro enzymatic analysis revealed that the MaDFR enzyme can reduce all the three types of dihydroflavonols (dihydrokaempferol, dihydroquercetin, and dihydromyricetin), although it most preferred dihydromyricetin as a substrate to produce leucodelphinidin, the precursor of blue-hued delphinidin. This indicated that there may be other functional genes responsible for the loss of red pelargonidin-based pigments in Muscari. To further verify the substrate-specific selection domains of MaDFR, an assay of amino acid substitutions was conducted. The activity of MaDFR was not affected whenever the N135 or E146 site was mutated. However, when both of them were mutated, the catalytic activity of MaDFR was lost completely. The results suggest that both the N135 and E146 sites are essential for the activity of MaDFR. Additionally, the heterologous expression of MaDFR in tobacco (Nicotiana tabacum) resulted in increasing anthocyanin accumulation, leading to a darker flower color, which suggested that MaDFR was involved in color development in flowers. In summary, MaDFR has a high preference for dihydromyricetin, and it could be a powerful candidate gene for genetic engineering for blue flower colour modification. Our results also make a valuable contribution to understanding the basis of color variation in the genus Muscari.

Project description:Tea (Camellia sinensis) is one of the richest sources of flavan-3-ols, an important class of flavonoids. The expression level of gene-encoded key regulatory enzymes of flavan-3-ol/anthocyanin biosynthetic pathway, dihydroflavonol 4-reductase (DFR) and anthocyanidin reductase (ANR), has been highly correlated with the flavan-3-ol contents and antioxidant activity in tea plant. In the present study, pyramiding of CsDFR and CsANR in tobacco was achieved. However, single transgenic tobacco overexpressing either CsDFR or CsANR was documented earlier. In continuation, pyramided transgenic lines were evaluated for the possible, either same or beyond, effect on flavan-3-ol accumulation and protective ability against biotic and abiotic stresses. The pyramided transgenic lines showed early flowering and improved seed yield. The transcript levels of flavan-3-ol/anthocyanin biosynthetic pathway and related genes in pyramided transgenic lines were upregulated as compared to control tobacco plants. The accumulations of flavan-3-ols were also found to be higher in pyramided transgenic lines than control tobacco plants. In contrast, anthocyanin content was observed to be decreased in pyramided transgenic lines, while DPPH activity was higher in pyramided transgenic lines. In pyramided transgenic lines, strong protective ability against feeding by Spodoptera litura was documented. The seeds of pyramided transgenic lines were also found to have better germination rate under aluminum toxicity as compared to control tobacco plants. Interestingly, the synergistic effect of these two selected genes are not beyond from transgenic lines expressing either CsDFR and CsANR alone as published earlier in terms of flavan-3-ols accumulation. However, the unique flower color and better seed germination rate are some interestingly comparable differences that were reported in pyramided lines in relation to individual transgenic plants. In conclusion, the present results reveal an interesting dynamic between CsDFR and CsANR in modulating flavan-3-ol/anthocyanin levels and functional analysis of stacked CsDFR and CsANR transgenic tobacco lines.

Project description:Dihydroflavonol 4-reductase (DFR) is the key enzyme committed to anthocyanin and proanthocyanidin biosynthesis in the flavonoid biosynthetic pathway. DFR proteins can catalyse mainly the three substrates (dihydrokaempferol, dihydroquercetin, and dihydromyricetin), and show different substrate preferences. Although relationships between the substrate preference and amino acids in the region responsible for substrate specificity have been investigated in several plant species, the molecular basis of the substrate preference of DFR is not yet fully understood.By using degenerate primers in a PCR, we isolated two cDNA clones that encoded DFR in buckwheat (Fagopyrum esculentum). Based on sequence similarity, one cDNA clone (FeDFR1a) was identical to the FeDFR in DNA databases (DDBJ/Gen Bank/EMBL). The other cDNA clone, FeDFR2, had a similar sequence to FeDFR1a, but a different exon-intron structure. Linkage analysis in an F2 segregating population showed that the two loci were linked. Unlike common DFR proteins in other plant species, FeDFR2 contained a valine instead of the typical asparagine at the third position and an extra glycine between sites 6 and 7 in the region that determines substrate specificity, and showed less activity against dihydrokaempferol than did FeDFR1a with an asparagine at the third position. Our 3D model suggested that the third residue and its neighbouring residues contribute to substrate specificity. FeDFR1a was expressed in all organs that we investigated, whereas FeDFR2 was preferentially expressed in roots and seeds.We isolated two buckwheat cDNA clones of DFR genes. FeDFR2 has unique structural and functional features that differ from those of previously reported DFRs in other plants. The 3D model suggested that not only the amino acid at the third position but also its neighbouring residues that are involved in the formation of the substrate-binding pocket play important roles in determining substrate preferences. The unique characteristics of FeDFR2 would provide a useful tool for future studies on the substrate specificity and organ-specific expression of DFRs.

Dataset Information

Structure prediction of dihydroflavonol 4- reductase and anthocyanidin synthase from spinach.

Publications

Structure prediction of dihydroflavonol 4- reductase and anthocyanidin synthase from spinach.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure