• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.931-937
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• 2018

Glycosyltransferases (GTs) from microbes are an emerging and rich source for efficient glycol-transformation of natural/unnatural compounds. Here, we probed the catalytic capability and substrate promiscuity of BmmGT1 from marine-derived Bacillus methylotrophicus B-9987. The regioselectivity of BmmGT1 on macrolactin A (1) was explored by optimization of the reaction conditions, in which a series of O-glycosylated macrolactins (1a-1e) were generated, including two new di/tri-O-glucosyl analogs (1b and 1e). Furthermore, BmmGT1 was able to catalyze the glycosylation of the thiol (S-) or amine (N-) sites of phenolic compounds (2 and 3), leading to the generation of N- (2a) or S-glycosides (3a and 3b). The present study demonstrates that BmmGT1 could serve as a potential enzyme tool for O-, N-, or S-glycosyl structural diversification of compounds for drug discovery.

• Journal of Ginseng Research
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• 제45권1호
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• pp.58-65
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• 2021

Background: Panax ginseng, as one of the most widely used herbal medicines worldwide, has been studied comprehensively in terms of the chemical components and pharmacology. The proteins from ginseng are also of great importance for both nutrition value and the mechanism of secondary metabolites. However, the proteomic studies are less reported in the absence of the genome information. With the completion of ginseng genome sequencing, the proteome profiling has become available for the functional study of ginseng protein components. Methods: We optimized the protein extraction process systematically by using SDS-PAGE and one-dimensional liquid chromatography mass spectrometry. The extracted proteins were then analyzed by two-dimensional chromatography separation and cutting-edge mass spectrometry technique. Results: A total of 2,732 and 3,608 proteins were identified from ginseng root and cauline leaf, respectively, which was the largest data set reported so far. Only around 50% protein overlapped between the cauline leaf and root tissue parts because of the function assignment for plant growing. Further gene ontology and KEGG pathway revealed the distinguish difference between ginseng root and leaf, which accounts for the photosynthesis and metabolic process. With in-deep analysis of functional proteins related to ginsenoside synthesis, we interestingly found the cytochrome P450 and UDP-glycosyltransferase expression extensively in cauline leaf but not in the root, indicating that the post glucoside synthesis of ginsenosides might be carried out when growing and then transported to the root at withering. Conclusion: The systematically proteome analysis of Panax ginseng will provide us comprehensive understanding of ginsenoside synthesis and guidance for artificial cultivation.

• Journal of Microbiology and Biotechnology
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• 제33권4호
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• pp.519-526
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• 2023

Panax ginseng is one of the most important herbal medicinal plants consumed as health functional food and can be fermented to achieve better efficacy. Lacticaseibacillus, one of the representative genera among lactic acid bacteria (LAB), has also been used as a probiotic material for health functional foods due to its beneficial effects on the human body. To achieve a synergistic effect by using these excellent dietary supplement ingredients together, a novel LAB strain was isolated from the root of 6-year-old ginseng. Through similarity analysis of 16S rRNAs and whole-genome sequences, the strain was confirmed as belonging to the genus Lacticaseibacillus and was named L. casei KGC1201. KGC1201 not only met all safety standards as food, but also showed excellent probiotic properties such as acid resistance, bile salt resistance, and intestinal adhesion. In particular, KGC1201 exhibited superior acid resistance through morphological observation identifying that the cell surface damage of KGC1201 was less than that of the L. casei type strain KCTC3109. Gene expression studies were conducted to elucidate the molecular mechanisms of KGC1201's acid resistance, and the expression of the glycosyltransferase gene was found to be significantly elevated under acidic conditions. Exopolysaccharides (EPSs) biosynthesized by glycosyltransferase were also increased in KGC1201 compared to KCTC3109, which may contribute to better protection of KGC1201 cells from strong acidity. Therefore, KGC1201, with its increased acid resistance through molecular mechanisms and excellent probiotic properties, can be used in health functional foods to provide greater benefit to overall human health and well-being.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1154-1163
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• 2024

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4'-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4',7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4',5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.1909-1921
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• 2007

Significant progress has recently been made concerning the engineering of deoxysugar biosynthesis. The biosynthetic gene clusters of several deoxysugars from various polyketides and aminoglycosides-producing microorganisms have been cloned and studied. This review introduces the biosynthetic pathways of several deoxysugars and the generation of novel hybrid macrolide antibiotics via the coexpression of deoxysugar biosynthetic gene cassettes and the substrate-flexible glycosyltransferases in a host organism as well as the production of TDP-deoxysugar derivatives via one-pot enzymatic reactions with the identified enzymes. These recent developments in the engineering of deoxysugars biosynthesis may pave the way to create novel secondary metabolites with potential biological activities.

• 한국식품영양학회지
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• 제8권3호
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• pp.253-261
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• 1995

A strain of alkalophilic Bacillus sp. C-21 has been Isolated from sold. The strain was capable of producing large amount of cyclodextrin glycosyltransferase (CGTase) in the high alkaline pH medium. The preferable medium composition was determined to be as follows : 1.0% soluble starch, 1.0% peptone, 0.5% yeast extract, 0.1% K2HP04, 0.02% MgSO4.7H2O and 1.0% Na2CO3(pH 10.0) The highest enzyme production was observed after 30hours of cultivation at 33$^{\circ}C$. The optimum temperature and pH for the activity of crude enzyme were 6$0^{\circ}C$ and 6.0, respectively. The enzyme was stable between pH 6.0 and 9.6, and up to 55$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.298-304
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• 2018

The single-vessel multienzyme UDP-${\alpha}$-$\text\tiny{D}$-glucose recycling system was coupled with a forward glucosylation reaction to produce novel glucose moiety-conjugated derivatives of different tetracycline antibiotic analogs. Among five tetracycline analogs used for the reaction, four molecules (chlorotetracycline, doxytetracycline, meclotetracycline, and minotetracycline) were accepted by a glycosyltransferase enzyme, YjiC, from Bacillus licheniformis to produce glucoside derivatives. However, the enzyme was unable to conjugate sugar units to rolitetracycline. All glucosides of tetracycline derivatives were characterized by ultraviolet absorbance maxima, ultra-pressure liquid chromatography coupled with photodiode array, and high-resolution quadruple time-of-flight electrospray mass spectrometry analyses. These synthesized glucosides are novel tetracycline derivatives.

• BMB Reports
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• 제40권6호
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• pp.870-874
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• 2007

We cloned a uridine-diphosphate dependent glycosyl-transferase RUGT-10 from Oryza sativa. The recombinant enzyme was expressed by glutathione-S transferase gene fusion system in Escherichia coli. RUGT10 showed different regioselectivity depending on the structures of substrates (e.g. flavanone, flavonol, and flavone). Apparently, flavanone such as naringenin and eriodictyol gave one 7-O-glucoside while flavone and flavonol gave more than two products with preferential glucosylation position of hydroxyl group at C-3 position.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.97-100
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• 1997

Cyclodxtrin homologues(CDs), produced by cyclodextrin glycosyltransferase(CGTase), were simultaneously partitioned in aqueous two-phase system(ATPS). Partition coefficients of CDs were measured in PEG/dextran systems. Phosphate, citrate, sulfate were tested as salt. ATPS of PEG/salt and PEG/dextran had the partition coefficients of the CDs, larger than unity. However, PEG/dextran system was observed better than PEG/salt as CGTase activity decreased sharply with salt concentration. Enzymatic rection occurred mainly in PEG-rich bottom phase because of the low partition coefficient of CGTase. The resulting CDs transferred to the PEG-rich top phase, obeying the diffusional partition. In the ATPS of 7% PEG(M.W.40, 000), 7mg/ml of CDs were obtained in top phase at 4.5 hours.

• Molecules and Cells
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• 제26권3호
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• pp.278-284
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• 2008

An open reading frame, designated GerGTII and located downstream of the polyketide synthase genes, has been identified as a chalcosyltransferase by sequence analysis in the dihydrochalcomycin biosynthetic gene cluster of Streptomyces sp. KCTC 0041BP. The deduced product of gerGTII is similar to several glycosyltransferases, authentic and putative, and it displays a consensus sequence motif that appears to be characteristic of a sub-group of these enzymes. Specific disruption of gerGTII within the S. sp. KCTC 0041BP genome by insertional in-frame deletion method, resulted complete abolishment of dihydrochalcomycin and got the 20-O-mycinosyl-dihydrochalconolide as intermediate product in dihydrochalcomycin biosynthesis which was confirmed by electron spray ionization-mass spectrometry and liquid chromatography-mass spectrometry. Dihydrochalcomycin also was recovered after complementation of gerGTII.