Substrate specificity of plant UDP-dependent glycosyltransferases predicted from crystal structures and homology modeling

Osmani, Sarah A.; Bak, Søren; Møller, Birger Lindberg

doi:10.1016/j.phytochem.2008.12.009

Cited by 229 publications

(263 citation statements)

References 102 publications

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“…VvGT1 and Mt71G1 accept flavonols as donor substrates and therefore were selected for sequence and structural comparison. Previous analysis of four plant UDP-dependent glycosyltransferases revealed a low overall conservation on the protein sequence level, but a high conservation on the level of secondary and tertiary protein structure (56). The alignment (Fig.…”

Section: Altered Flavonol Glycosylation Suppresses the Rol1-2 Shootmentioning

confidence: 89%

7-Rhamnosylated Flavonols Modulate Homeostasis of the Plant Hormone Auxin and Affect Plant Development

Kuhn

Errafi

Bucher

et al. 2016

Journal of Biological Chemistry

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Flavonols are a group of secondary metabolites that affect diverse cellular processes. They are considered putative negative regulators of the transport of the phytohormone auxin, by which they influence auxin distribution and concomitantly take part in the control of plant organ development. Flavonols are accumulating in a large number of glycosidic forms. Whether these have distinct functions and diverse cellular targets is not well understood. The rol1-2 mutant of Arabidopsis thaliana is characterized by a modified flavonol glycosylation profile that is inducing changes in auxin transport and growth defects in shoot tissues. To determine whether specific flavonol glycosides are responsible for these phenotypes, a suppressor screen was performed on the rol1-2 mutant, resulting in the identification of an allelic series of UGT89C1, a gene encoding a flavonol 7-O-rhamnosyltransferase. A detailed analysis revealed that interfering with flavonol rhamnosylation increases the concentration of auxin precursors and auxin metabolites, whereas auxin transport is not affected. This finding provides an additional level of complexity to the possible ways by which flavonols influence auxin distribution and suggests that flavonol glycosides play an important role in regulating plant development.

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Section: Altered Flavonol Glycosylation Suppresses the Rol1-2 Shootmentioning

confidence: 89%

7-Rhamnosylated Flavonols Modulate Homeostasis of the Plant Hormone Auxin and Affect Plant Development

Kuhn

Errafi

Bucher

et al. 2016

Journal of Biological Chemistry

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“…Modeling revealed the overall folds of the two ␤/␣/␤ Rossman domains to be clearly conserved in the two proteins, with only a few smaller insertions and deletions in the loop regions. Similarly, there were no obvious differences in the conformation of the active site residues that could account for the unusual C-conjugating activity of OsCGT or the potential of the enzyme to use sugar donors other than UDP-glucose in the plant secondary product glucosyltransferase binding domain (40).…”

Section: Discussionmentioning

confidence: 99%

The C-Glycosylation of Flavonoids in Cereals

Brazier-Hicks

Evans

Gershater

et al. 2009

Journal of Biological Chemistry

262

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Flavonoids normally accumulate in plants as O-glycosylated derivatives, but several species, including major cereal crops, predominantly synthesize flavone-C-glycosides, which are stable to hydrolysis and are biologically active both in planta and as dietary components. An enzyme (OsCGT) catalyzing the UDPglucose-dependent C-glucosylation of 2-hydroxyflavanone precursors of flavonoids has been identified and cloned from rice (Oryza sativa ssp. indica), with a similar protein characterized in wheat (Triticum aestivum L.). OsCGT is a 49-kDa family 1 glycosyltransferase related to known O-glucosyltransferases. The recombinant enzyme C-glucosylated 2-hydroxyflavanones but had negligible O-glucosyltransferase activity with flavonoid acceptors. Enzyme chemistry studies suggested that OsCGT preferentially C-glucosylated the dibenzoylmethane tautomers formed in equilibrium with 2-hydroxyflavanones. The resulting 2-hydroxyflavanone-C-glucosides were unstable and spontaneously dehydrated in vitro to yield a mixture of 6C-and 8C-glucosyl derivatives of the respective flavones. In contrast, in planta, only the respective 6C-glucosides accumulated. Consistent with this selectivity in glycosylation product, a dehydratase activity that preferentially converted 2-hydroxyflavanone-Cglucosides to the corresponding flavone-6C-glucosides was identified in both rice and wheat. Our results demonstrate that cereal crops synthesize C-glucosylated flavones through the concerted action of a CGT and dehydratase acting on activated 2-hydroxyflavanones, as an alternative means of generating flavonoid metabolites.

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“…molecules such as flavonoids, terpenoids, and benzoates are glycosylated by enzymes of the family 1 UDP glycosyltransferases (UGTs; Osmani et al, 2009). These UGTs comprise a diverse group of enzymes, which all contain a highly conserved 44-amino acid plant secondary product glycosyltransferase (PSPG) motif.…”

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confidence: 99%

“…Members of the family 1 UGTs show high variability in their substrate specificity. Some of these enzymes glycosylate a broad range of acceptor molecules, while other UGTs act on only one or a few substrates (Osmani et al, 2009). Despite their large differences in acceptor preference and low sequence conservation, UGTs are conserved in their secondary and tertiary structures.…”

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confidence: 99%

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A Conifer UDP-Sugar Dependent Glycosyltransferase Contributes to Acetophenone Metabolism and Defense against Insects

et al. 2017

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ORCID IDs: 0000-0001-7801-1007 (M.H.M.); 0000-0003-4788-1565 (B.S.); 0000-0002-3637-7956 (J.B.).Acetophenones are phenolic compounds involved in the resistance of white spruce (Picea glauca) against spruce budworm (Choristoneura fumiferiana), a major forest pest in North America. The acetophenones pungenol and piceol commonly accumulate in spruce foliage in the form of the corresponding glycosides, pungenin and picein. These glycosides appear to be inactive against the insect but can be cleaved by a spruce b-glucosidase, PgbGLU-1, which releases the active aglycons. The reverse glycosylation reaction was hypothesized to involve a family 1 UDP-sugar dependent glycosyltransferase (UGT) to facilitate acetophenone accumulation in the plant. Metabolite and transcriptome profiling over a developmental time course of white spruce bud burst and shoot growth revealed two UGTs, PgUGT5 and PgUGT5b, that glycosylate pungenol. Recombinant PgUGT5b enzyme produced mostly pungenin, while PgUGT5 produced mostly isopungenin. Both UGTs also were active in vitro on select flavonoids. However, the context of transcript and metabolite accumulation did not support a biological role in flavonoid metabolism but correlated with the formation of pungenin in growing shoots. Transcript levels of PgUGT5b were higher than those of PgUGT5 in needles across different genotypes of white spruce. These results support a role of PgUGT5b in the biosynthesis of the glycosylated acetophenone pungenin in white spruce.

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Substrate specificity of plant UDP-dependent glycosyltransferases predicted from crystal structures and homology modeling

Cited by 229 publications

References 102 publications

7-Rhamnosylated Flavonols Modulate Homeostasis of the Plant Hormone Auxin and Affect Plant Development

7-Rhamnosylated Flavonols Modulate Homeostasis of the Plant Hormone Auxin and Affect Plant Development

The C-Glycosylation of Flavonoids in Cereals

A Conifer UDP-Sugar Dependent Glycosyltransferase Contributes to Acetophenone Metabolism and Defense against Insects

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