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Celina Bermúdez, Isabel Peña, Santiago Mata, José L Alonso
The conformational behaviour of naturally occurring ketohexoses has been revealed in a supersonic expansion by Fourier transform microwave spectroscopy coupled with a laser ablation source. Three, two and one conformers of d-tagatose, d-psicose and l-sorbose, respectively, have been identified by their rotational constants extracted from the analysis of the spectra. Singular structural signatures involving the hydroxyl groups OH(1) and OH(2) have been disentangled from the intricate intramolecular hydrogen bond networks stabilising the most abundant conformers...
October 4, 2016: Chemistry: a European Journal
Weiwei He, Bo Jiang, Wanmeng Mu, Tao Zhang
The production of d-allulose is usually conducted via isolated-enzyme or whole-cell biocatalysis reactions. In the present study, an innovative biocatalyst, d-psicose 3-epimerase (DPEase) from Clostridium scindens ATCC 35704, presented on the surface of Bacillus subtilis spores, was applied for d-allulose production. DPEase was fused at the C-terminus of the anchoring protein, CotZ, via a peptide linker, and trophic genes were used as selection markers during the chromosomal integration. The optimal temperature and pH of the fusion protein CotZ-DPEase were 55 °C and pH 7...
September 28, 2016: Journal of Agricultural and Food Chemistry
Liuqing Wen, Kenneth Huang, Yuan Zheng, Junqiang Fang, Shukkoor Muhammed Kondengaden, Peng George Wang
Rare sugars offer a plethora of applications in the pharmaceutical, medicinal, and industries, as well as in synthetic chemistry. However, studies of rare sugars have been hampered by their relative scarcity. In this work, we describe a two-step strategy to efficiently and conveniently prepare 6-deoxy-L-psicose from L-rhamnose. In the first reaction step, the isomerization of L-rhamnose (6-deoxy-L-mannose) to L-rhamnulose (6-deoxy-L-fructose) catalyzed by L-rhamnose isomerase (RhaI), and the epimerization of L-rhamnulose to 6-deoxy-L-psicose catalyzed by D-tagatose 3-epimerase (DTE) were coupled with selective phosphorylation reaction by fructose kinase from human (HK), which selectively phosphorylate 6-deoxy-L-psicose at C-1 position...
August 24, 2016: Tetrahedron Letters
Jingqi Chen, Yueming Zhu, Gang Fu, Yafeng Song, Zhaoxia Jin, Yuanxia Sun, Dawei Zhang
D-Psicose 3-epimerase (DPEase) converts D-fructose into D-psicose which exists in nature in limited quantities and has key physiological functions. In this study, RDPE (DPEase from Ruminococcus sp. 5_1_39BFAA) was successfully constitutively expressed in Bacillus subtilis, which is the first report of its kind. Three sugar-inducible promoters were compared, and the xylose-inducible promoter P xylA was proved to be the most efficient for RDPE production. Based on the analysis of the inducer concentration and RDPE expression, we surmised that there was an extremely close correlation between the intracellular RDPE expression and xylose accumulation level...
November 2016: Journal of Industrial Microbiology & Biotechnology
Manisha Sharma, Satya Narayan Patel, Kusum Lata, Umesh Singh, Meena Krishania, Rajender S Sangwan, Sudhir P Singh
In this work, the sugar industry by-product cane molasses was investigated as feedstock for acceptor reactions by dextransucrase from Leuconostoc mesenteroides MTCC 10508, leading to the biosynthesis of oligosaccharides. The starch industry corn fiber residue was used as a source for acceptor molecules, maltose, in the reaction. Production of approximately 124g oligosaccharides (DP3-DP6) per kg of fresh molasses was achieved. Further, cane molasses based medium was demonstrated as a sole carbon source for L...
November 2016: Bioresource Technology
Dong-Ho Chang, Moon-Soo Rhee, Ji-Sun Kim, Yookyung Lee, Mi Young Park, Haseong Kim, Seung-Goo Lee, Byoung-Chan Kim
Two bacterial strains, 46-1 and 46-2(T), were isolated from garden soil. These strains were observed to be aerobic, Gram-stain negative, rod-shaped, non-spore-forming, motile and catalase and oxidase positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that the two strains shared 100 % sequence similarity with each other and belong to the genus Pseudomonas in the class Gammaproteobacteria. The concatenated 16S rRNA, gyrB, rpoB and rpoD gene sequences further confirmed that the isolates belong to the Pseudomonas koreensis subgroup (SG), with P...
November 2016: Antonie Van Leeuwenhoek
Hiromi Yoshida, Akihide Yoshihara, Tomohiko Ishii, Ken Izumori, Shigehiro Kamitori
Pseudomonas cichorii D-tagatose 3-epimerase (PcDTE), which has a broad substrate specificity, efficiently catalyzes the epimerization of not only D-tagatose to D-sorbose but also D-fructose to D-psicose (D-allulose) and also recognizes the deoxy sugars as substrates. In an attempt to elucidate the substrate recognition and catalytic reaction mechanisms of PcDTE for deoxy sugars, the X-ray structures of the PcDTE mutant form with the replacement of Cys66 by Ser (PcDTE_C66S) in complexes with deoxy sugars were determined...
July 1, 2016: Applied Microbiology and Biotechnology
Weiwei He, Wanmeng Mu, Bo Jiang, Xin Yan, Tao Zhang
An integrative food-grade expression system with tandem repeat target genes was constructed for the expression of d-psicose 3-epimerase (DPEase; EC The DPEase gene fused with the P43 promoter constituted an independent monomeric expression cassette. Multimers of the expression cassette were constructed in vitro using the isocaudamer strategy. The recombinant integration plasmids pDG-nDPE (n = 1, 2, 3), which contained one, two, or three consecutive P43-DPEase tandem repeats, were integrated into the genome of B...
July 20, 2016: Journal of Agricultural and Food Chemistry
Robert-Jan van Putten, Jan C van der Waal, Martin Harmse, Henk H van de Bovenkamp, Ed de Jong, Hero J Heeres
The acid-catalysed dehydration of the four 2-ketohexoses (fructose, sorbose, tagatose and psicose) to furanics was studied in methanol (65 g L(-1) substrate concentration, 17 and 34 mm sulfuric acid, 100 °C) with Avantium high-throughput technology. Significant differences in the reactivities of the hexoses and yields of 5-hydroxymethylfurfural (HMF) and its methyl ether (MMF) were observed. Psicose and tagatose were the most reactive, and psicose also afforded the highest combined yield of MMF and HMF of approximately 55 % at 96 % sugar conversion...
July 21, 2016: ChemSusChem
Syed Muniruzzaman, Megan McIntosh, Ahamed Hossain, Ken Izumori, Partha S Bhattacharjee
PURPOSE: To determine the therapeutic efficacy of a novel rare sugar, l-psicose, for the treatment of HSV-1 induced herpetic stromal keratitis (HSK) in a mouse eye model. METHODS: One rare sugar l-psicose was assayed for HSV-1 inhibition of in vitro virus adsorption. The IC50 and IC90 values of l-psicose were determined using plaque reduction assay (PRA) in CV-1 cell. Female Balb/c mice were corneally infected with HSV-1, strain KOS-GFP; A topical eye drop treatment of l-psicose was started 24 h after infection and continued four times daily for ten consecutive days...
June 2016: Journal of Pharmacological Sciences
Satya Narayan Patel, Manisha Sharma, Kusum Lata, Umesh Singh, Vinod Kumar, Rajender S Sangwan, Sudhir P Singh
The aim of the present work was to improve stability of d-psicose 3-epimerase and biotransformation of fruit and vegetable residues for d-psicose production. The study established that N-terminal fusion of a yeast homolog of SUMO protein - Smt3 - can confer elevated optimal temperature and improved operational stability to d-psicose 3-epimerase. The Smt3-d-psicose 3-epimerase conjugate system exhibited relatively better catalytic efficiency, and improved productivity in terms of space-time yields of about 8...
September 2016: Bioresource Technology
Kiran S Dhar, Volker F Wendisch, Kesavan Madhavan Nampoothiri
Xylitol is a non-fermentable sugar alcohol used as sweetener. Corynebacterium glutamicum ATCC13032 was metabolically engineered for xylitol production from the lignocellulosic pentose sugars xylose and arabinose. Direct conversion of xylose to xylitol was achieved through the heterologous expression of NAD(P)H-dependent xylose reductase (xr) gene from Rhodotorula mucilaginosa. Xylitol synthesis from arabinose was attained through polycistronic expression of l-arabinose isomerase (araA), d-psicose 3 epimerase (dpe) and l-xylulose reductase (lxr) genes from Escherichia coli, Agrobacterium tumefaciens and Mycobacterium smegmatis, respectively...
July 20, 2016: Journal of Biotechnology
Jingqi Chen, Liuqun Zhao, Gang Fu, Wenjuan Zhou, Yuanxia Sun, Ping Zheng, Jibin Sun, Dawei Zhang
BACKGROUND: The Gram-positive bacterium Bacillus subtilis has been widely used as a cell factory for the production of proteins due to its generally regarded as safe (GRAS) nature and secretion capability. Of the known secretory pathways in B. subtilis, the majority of proteins are exported from the cytoplasm by Sec pathway, Tat pathway and ABC transporters, etc. However, the production of heterologous proteins by B. subtilis is unfortunately not that straight forward because of the bottlenecks in classical secretion pathways...
2016: Microbial Cell Factories
Wenli Zhang, Min Jia, Shuhuai Yu, Tao Zhang, Leon Zhou, Bo Jiang, Wanmeng Mu
d-Psicose is a highly valuable rare sugar because of its excellent physiological properties and commercial potential. d-Psicose 3-epimerase (DPEase) is the key enzyme catalyzing the isomerization of d-fructose to d-psicose. However, the poor thermostability and low catalytic efficiency are serious constraints on industrial application. To address these issues, site-directed mutagenesis of Tyr68 and Gly109 of the Clostridium bolteae DPEase was performed. Compared with the wild-type enzyme, the Y68I variant displayed the highest substrate-binding affinity and catalytic efficiency, and the G109P variant showed the highest thermostability...
May 4, 2016: Journal of Agricultural and Food Chemistry
Weiwei He, Wanmeng Mu, Bo Jiang, Xin Yan, Tao Zhang
A food grade recombinant Bacillus subtilis that produces d-psicose 3-epimerase (DPEase; EC was constructed by transforming a replicative multicopy plasmid with a d-alanine racemase gene marker into B. subtilis 1A751 with the d-alanine racemase gene knocked out. The DPEase was expressed in B. subtilis without antibiotic resistance genes and without adding antibiotics during fermentation. Whole cells of the food grade recombinant B. subtilis were used to biotransform d-fructose to d-allulose. The two tandem promoters, including the HpaII and P43 promoters, increased expression levels compared to the use of one promoter, HpaII...
April 27, 2016: Journal of Agricultural and Food Chemistry
Peng-Fei Xia, Guo-Chang Zhang, Jing-Jing Liu, Suryang Kwak, Ching-Sung Tsai, In Iok Kong, Bong Hyun Sung, Jung-Hoon Sohn, Shu-Guang Wang, Yong-Su Jin
Rapid advances in the capabilities of reading and writing DNA along with increasing understanding of microbial metabolism at the systems-level have paved an incredible path for metabolic engineering. Despite these advances, post-translational tools facilitating functional expression of heterologous enzymes in model hosts have not been developed well. Some bacterial enzymes, such as Escherichia coli xylose isomerase (XI) and arabinose isomerase (AI) which are essential for utilizing cellulosic sugars, cannot be functionally expressed in Saccharomyces cerevisiae...
October 2016: Biotechnology and Bioengineering
Wojciech Plazinski, Anita Plazinska, Mateusz Drach
The molecular properties of aldohexoses and ketohexoses are usually studied in the context of their cyclic, furanose or pyranose structures which is due to the abundance of related tautomeric forms in aqueous solution. We studied the conformational features of a complete series of D-aldohexoses (D-allose, D-altrose, D-glucose, D-mannose, D-gulose, d-idose, D-galactose and D-talose) and D-ketohexoses (D-psicose, D-fructose, D-sorbose and D-tagatose) as well as of L-psicose by using microsecond-timescale molecular dynamics in explicit water and DMSO with the use of enhanced sampling methods...
April 14, 2016: Physical Chemistry Chemical Physics: PCCP
Naohito Nishii, Toru Nomizo, Satoshi Takashima, Tatsuya Matsubara, Masaaki Tokuda, Hitoshi Kitagawa
Healthy dogs were administered acute oral doses of D-allulose (also called D-psicose) to evaluate its toxicity. Six dogs received oral doses of either a placebo or D-allulose solution (1 and 4 g/kg) on three different study days. One dog experienced vomiting, and five dogs showed transient diarrhea when 4 g/kg of D-allulose was administered. All dogs were active and had a good appetite throughout the study period. Blood glucose concentration slightly decreased without a rise in plasma insulin concentration 2 hr after D-allulose administration...
July 1, 2016: Journal of Veterinary Medical Science
Youngji Han, Hye Jin Han, Ae-Hyang Kim, Ji-Young Choi, Su-Jung Cho, Yong Bok Park, Un Ju Jung, Myung-Sook Choi
SCOPE: A number of findings suggest that zero-calorie d-allulose, also known as d-psicose, has beneficial effects on obesity-related metabolic disturbances. However, it is unclear whether d-allulose can normalize the metabolic status of diet-induced obesity without having an impact on the energy density. We investigated whether 5% d-allulose supplementation in a high fat diet(HFD) could normalize body fat in a diet-induced obesity animal model under isocaloric pair-fed conditions. METHODS AND RESULTS: Mice were fed an HFD with or without various sugar substitutes (d-glucose, d-fructose, erytritol, or d-allulose, n = 10 per group) for 16 wk...
July 2016: Molecular Nutrition & Food Research
Akihide Yoshihara, Tomohiko Ishii, Tatsuya Kamakura, Hiroaki Taguchi, Kazuhiro Fukada
The title compound, C6H12O5, was crystallized from an aqueous solution of 6-de-oxy-l-psicose (6-de-oxy-l-allulose, (3S,4S,5S)-1,3,4,5-tetra-hydroxy-hexan-2-one), and the mol-ecule was confirmed as α-furan-ose with a (3) T 4 (or E 4) conformation, which is a predominant tautomer in solution. This five-membered furan-ose ring structure is the second example in the field of the 6-de-oxy-ketohexose family. The cell volume of the title compound [742.67 (7) Å(3), Z = 4 at room temperature] is only 1.4% smaller than that of β-d-psico-pyran-ose, C6H12O6 (753...
December 1, 2015: Acta Crystallographica. Section E, Crystallographic Communications
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