Reaction participants Show >> << Hide
- Name help_outline rebaudioside A Identifier CHEBI:145012 (CAS: 58543-16-1) help_outline Charge 0 Formula C44H70O23 InChIKeyhelp_outline HELXLJCILKEWJH-NCGAPWICSA-N SMILEShelp_outline [C@]123[C@]([C@]4([C@@]([C@](CCC4)(C)C(O[C@@H]5O[C@@H]([C@@H](O)[C@@H]([C@H]5O)O)CO)=O)(CC1)[H])C)(CC[C@@](C2)(O[C@H]6[C@H](O[C@@H]7O[C@@H]([C@@H](O)[C@@H]([C@H]7O)O)CO)[C@H]([C@H](O)[C@H](O6)CO)O[C@@H]8O[C@@H]([C@@H](O)[C@@H]([C@H]8O)O)CO)C(C3)=C)[H] 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-α-D-glucose Identifier CHEBI:58885 (Beilstein: 3827329) help_outline Charge -2 Formula C15H22N2O17P2 InChIKeyhelp_outline HSCJRCZFDFQWRP-JZMIEXBBSA-L SMILEShelp_outline OC[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2ccc(=O)[nH]c2=O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 272 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline rebaudioside D Identifier CHEBI:145022 (CAS: 63279-13-0) help_outline Charge 0 Formula C50H80O28 InChIKeyhelp_outline RPYRMTHVSUWHSV-CUZJHZIBSA-N SMILEShelp_outline [C@]123[C@]([C@]4([C@@]([C@](CCC4)(C)C(O[C@@H]5O[C@@H]([C@@H](O)[C@@H]([C@H]5O[C@@H]6O[C@@H]([C@@H](O)[C@@H]([C@H]6O)O)CO)O)CO)=O)(CC1)[H])C)(CC[C@@](C2)(O[C@H]7[C@H](O[C@@H]8O[C@@H]([C@@H](O)[C@@H]([C@H]8O)O)CO)[C@H]([C@H](O)[C@H](O7)CO)O[C@@H]9O[C@@H]([C@@H](O)[C@@H]([C@H]9O)O)CO)C(C3)=C)[H] 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKeyhelp_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 711 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 10,232 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:61768 | RHEA:61769 | RHEA:61770 | RHEA:61771 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Microbial production of next-generation stevia sweeteners.
Olsson K., Carlsen S., Semmler A., Simon E., Mikkelsen M.D., Moeller B.L.
<h4>Background</h4>The glucosyltransferase UGT76G1 from Stevia rebaudiana is a chameleon enzyme in the targeted biosynthesis of the next-generation premium stevia sweeteners, rebaudioside D (Reb D) and rebaudioside M (Reb M). These steviol glucosides carry five and six glucose units, respectively, ... >> More
<h4>Background</h4>The glucosyltransferase UGT76G1 from Stevia rebaudiana is a chameleon enzyme in the targeted biosynthesis of the next-generation premium stevia sweeteners, rebaudioside D (Reb D) and rebaudioside M (Reb M). These steviol glucosides carry five and six glucose units, respectively, and have low sweetness thresholds, high maximum sweet intensities and exhibit a greatly reduced lingering bitter taste compared to stevioside and rebaudioside A, the most abundant steviol glucosides in the leaves of Stevia rebaudiana.<h4>Results</h4>In the metabolic glycosylation grid leading to production of Reb D and Reb M, UGT76G1 was found to catalyze eight different reactions all involving 1,3-glucosylation of steviol C <sub>13</sub>- and C <sub>19</sub>-bound glucoses. Four of these reactions lead to Reb D and Reb M while the other four result in formation of side-products unwanted for production. In this work, side-product formation was reduced by targeted optimization of UGT76G1 towards 1,3 glucosylation of steviol glucosides that are already 1,2-diglucosylated. The optimization of UGT76G1 was based on homology modelling, which enabled identification of key target amino acids present in the substrate-binding pocket. These residues were then subjected to site-saturation mutagenesis and a mutant library containing a total of 1748 UGT76G1 variants was screened for increased accumulation of Reb D or M, as well as for decreased accumulation of side-products. This screen was performed in a Saccharomyces cerevisiae strain expressing all enzymes in the rebaudioside biosynthesis pathway except for UGT76G1.<h4>Conclusions</h4>Screening of the mutant library identified mutations with positive impact on the accumulation of Reb D and Reb M. The effect of the introduced mutations on other reactions in the metabolic grid was characterized. This screen made it possible to identify variants, such as UGT76G1<sub>Thr146Gly</sub> and UGT76G1<sub>His155Leu</sub>, which diminished accumulation of unwanted side-products and gave increased specific accumulation of the desired Reb D or Reb M sweeteners. This improvement in a key enzyme of the Stevia sweetener biosynthesis pathway represents a significant step towards the commercial production of next-generation stevia sweeteners. << Less
Microb. Cell Fact. 15:207-207(2016) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.