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- Name help_outline steviolmonoside Identifier CHEBI:145010 Charge -1 Formula C26H39O8 InChIKeyhelp_outline QSIDJGUAAUSPMG-CULFPKEHSA-M SMILEShelp_outline O=C([C@]1([C@@]2([C@]([C@]3([C@]4(C[C@@](CC3)(C(C4)=C)O[C@H]5[C@H](O)[C@H]([C@H](O)[C@H](O5)CO)O)CC2)[H])(CCC1)C)[H])C)[O-] 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 231 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 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline steviolbioside Identifier CHEBI:145009 Charge -1 Formula C32H49O13 InChIKeyhelp_outline OMHUCGDTACNQEX-OSHKXICASA-M SMILEShelp_outline O=C([C@]1([C@@]2([C@]([C@]3([C@]4(C[C@@](CC3)(C(C4)=C)O[C@H]5[C@H](O[C@H]6[C@H](O)[C@H]([C@H](O)[C@H](O6)CO)O)[C@H]([C@H](O)[C@H](O5)CO)O)CC2)[H])(CCC1)C)[H])C)[O-] 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 576 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:61740 | RHEA:61741 | RHEA:61742 | RHEA:61743 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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| MetaCyc help_outline |
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.
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Pathway mining-based integration of critical enzyme parts for de novo biosynthesis of steviolglycosides sweetener in Escherichia coli.
Wang J., Li S., Xiong Z., Wang Y.