Structural Basis of Product Inhibition by Arabinose and Xylose of the Thermostable GH43 β-1,4-xylosidase from Geobacillusthermoleovorans IT-08

Ali Rohman, Niels Van Oosterwijk, Ni Nyoman Tri Puspaningsih, Bauke W. Dijkstra (2018)

PloS one,Vol. 13 (4)

Complete degradation of the xylan backbone of hemicellulosic plant cell walls requires the synergistic action of endo-xylanases and ß-1,4-xylosidases. While endo-xylanases produce xylooligosaccharides from xylan, ß-1,4-xylosidases degrade the xylooligosaccharides into xylose monomers. The glycoside hydrolase family 43 ß-1,4-xylosidase from GeobacillusthermoleovoransIT-08 is a promising, heat stable catalyst for the saccharification of hemicellulosic material into simple fermentable sugars, but it is competitively inhibited by its products arabinose and xylose. As a first step to help overcome this problem, we elucidated crystal structures of the enzyme in the unliganded form and with bound products, at 1.7±2.0 Å resolution. The structures are very similar to those of other enzymes belonging to glycosidehydrolase family 43. Unexpectedly, the monosaccharides are bound in very different ways. Arabinose preferentially binds in subsite -1, while xylose exclusively interacts with subsite +1. These structures and sugar binding preferences suggest ways for improving the catalytic performance of the enzyme by rational mutational design.


Use of Keratinase to Maintain Pre-Washing Glycoprotein Profiles Of Edible Bird’s Nest

Budi Utomo, Djalal Rosyidi, Lilik Eka Radiati, Ni Nyoman Tri Puspaningsih, Wahyu Diah Proborini (2018)

Drug Invention Today, Vol 10 (2), ISSN: 0975-7619

Edible bird’s nests (EBNs), a delicacy made from bird nests of Collocaliaspp. swiftlets, are well known for also having health benefits. Washing processes for EBNs with water after harvesting the nests dissolve potential bioactives such as glycoproteins and reduce the potential health benefits of EBNs. One alternative washing method is use keratinase enzymes, but the impact on the glycoprotein profile of EBNs remains unknown. This research attempted to analyze glycoprotein profiles before and after washing with keratinase. Fourier transform infrared and nucleic molecular resonance were used to observe these profiles. The results showed that there is no change between the glycoprotein profiles of EBN before and after washing with keratinase. Thus, keratinase washing is effective in maintaining the profiles of glycoproteins in EBNs.

Keywords:Bioactive, Glycoprotein, Keratinase, Medicine

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Identification and Characterization of Thermophilic and Pectinolytic Bacteria Isolated From Gunung Pancar Hot Spring Bogor, Indonesia

Galih Ayhusta Laras, Mimin Nur Handayani, Laura Navika Yamani,Purkan And Ni Nyoman Tri Puspaningsih

AJMBES, Vol. 19 (3) (2017)

Thermophilic bacteria produce thermo stable enzymes that are essential in industrial processes and biotechnology, one of these is a pectinolytic enzyme. Most of the pectinolytic bacteria have growth at temperatures below 40°C, and optimal up to a temperature of 60°C. Pectinolytic enzyme serves to break down the complex polysaccharide from plant tissue into simple molecules such as galakturonic acids used widely in the food industry, for extraction of fruit by reducing turbidity and bitterness of fruit juices, oil extraction, fermentation of coffee and tea, textile industry, and processing of fiber plants and paper production. This study aims to identify phylogenetic of thermophilic bacteria that carry pectinolytic enzymes from the hot springs of Mount Pancar, Bogor with the identification and characterization of 16S rRNA pectinolytic enzymes as well as activity against specific substrate pectin. 16S rRNA gene amplification process was performed by PCR and amplicon obtained was determined nucleotide sequences by sequencing. The results of phylogenetic analysis showed that the isolates obtained have high homology with Anoxybacillus flavithermus, while the other isolates have homology with Geobacillus kaustopilus. Pectinase enzyme activity was measured using the DNS method and characterization of enzyme activity was carried out at a temperature of 40-90°C and pH 3-10, showing optimum activity at 60°C and 70°C at pH 5.0 and 6.0. Katalog: