Project description:Here, we present the complete genome of the extreme thermophile, Dictyoglomus thermophilum H-6-12 (phylum Dictyoglomi), which consists of 1,959,987 bp.
Project description:BACKGROUND:?-D-xylosidase is a vital exoglycosidase with the ability to hydrolyze xylooligosaccharides to xylose and to biotransform some saponins by cleaving outer ?-xylose. ?-D-xylosidase is widely used as one of the xylanolytic enzymes in a diverse range of applications, such as fuel, food and the pharmaceutical industry; therefore, more and more studies have focused on the thermostable and xylose-tolerant ?-D-xylosidases. RESULTS:A thermostable ?-xylosidase gene (xln-DT) of 1509 bp was cloned from Dictyoglomus thermophilum and expressed in E.coli BL21. According to the amino acid and phylogeny analyses, the ?-xylosidase Xln-DT is a novel ?-xylosidase of the GH family 39. The recombinant ?-xylosidase was purified, showing unique bands on SDS-PAGE, and had a protein molecular weight of 58.7 kDa. The ?-xylosidase Xln-DT showed an optimal activity at pH 6.0 and 75 °C, with p-nitrophenyl-?-D-xylopyranoside (pNPX) as a substrate. Xln-DT displayed stability over a pH range of 4.0-7.5 for 24 h and displayed thermotolerance below 85 °C. The values of the kinetic parameters K m and V max for pNPX were 1.66 mM and 78.46 U/mg, respectively. In particular, Xln-DT displayed high tolerance to xylose, with 60% activity in the presence of 3 M xylose. Xln-DT showed significant effects on the hydrolyzation of xylobiose. After 3 h, all the xylobiose tested was degraded into xylose. Moreover, ?-xylosidase Xln-DT had a high selectivity for cleaving the outer xylose moieties of natural saponins, such as notoginsenoside R1 and astragaloside IV, which produced the ginsenoside Rg1 with stronger anti-fatigue activity and produced cycloastragenol with stronger anti-aging activity, respectively. CONCLUSION:This study provides a novel GH 39 ?-xylosidase displaying extraordinary properties of highly catalytic activity at temperatures above 75 °C, remarkable hydrolyzing activity of xylooligosaccharides and rare saponins producing ability in the pharmaceutical and commercial industries.
Project description:Cellulose-based products constitute the great majority of municipal waste, and applications of cellulases in the conversion of waste biomass to biofuels will be a key technology in future biorefineries. Currently, multi-enzymatic pre-treatment of biomass is a crucial step in making carbohydrates more accessible for subsequent fermentation. Using bioinformatics analysis, endo-?-(1,4)-glucanase from Dictyoglomus thermophilum (DtCel5H) was identified as a new member of glycosyl hydrolase family 5. The gene encoding DtCel5H was cloned and the recombinant protein was overexpressed for crystallization and biophysical studies. Here, it is shown that this enzyme is active on cellulose substrates and is highly thermostable. Crystals suitable for crystallographic investigations were also obtained in different crystallization conditions. In particular, ordered crystals of DtCel5H were obtained using either ammonium sulfate or polyethylene glycol (PEG) as a precipitant agent. The crystals obtained in the presence of ammonium sulfate belonged to space group P32, with unit-cell parameters a = 73.1, b = 73.1, 73.1, c = 127.8?Å, and diffracted to 1.5?Å resolution, whereas the second crystal form belonged to the orthorhombic space group P212121, with unit-cell parameters a = 49.3, b = 67.9, c = 103.7?Å, and diffracted to 1.6?Å resolution. The crystal structure was solved in both space groups using molecular-replacement methods. Structure-activity and structure-stability studies of DtCel5H will provide insights for the design of high-performance enzymes.
| S-EPMC5947686 | biostudies-literature
Project description:Alkaline hot spring mRNA raw sequence reads
