Aspergillus oryzae produces a unique β-glucosidase, isoprimeverose-producing oligoxyloglucan hydrolase (IPase), that recognizes and releases isoprimeverose (α-D-xylopyranose-(1 → 6)-D-glucopyranose) units from the non-reducing ends of oligoxyloglucans. A gene encoding A. oryzae IPase, termed ipeA, was identified and expressed in Pichia pastoris.
View Article and Find Full Text PDFThe specificity of the aglycone-binding site of Escherichia coli alpha-xylosidase (YicI), which belongs to glycoside hydrolase family 31, was characterized by examining the enzyme's transxylosylation-catalyzing property. Acceptor specificity and regioselectivity were investigated using various sugars as acceptor substrates and alpha-xylosyl fluoride as the donor substrate. Comparison of the rate of formation of the glycosyl-enzyme intermediate and the transfer product yield using various acceptor substrates showed that glucose is the best complementary acceptor at the aglycone-binding site.
View Article and Find Full Text PDFOligoxyloglucan reducing end-specific cellobiohydrolase (OXG-RCBH) is a unique exo-beta-1,4-glucanase that belongs to glycoside hydrolase family 74. The enzyme recognizes the reducing end of xyloglucan oligosaccharides and releases two glucosyl residue segments from the reducing end of the main chain. Previously, we reported that OXG-RCBH consists of two seven-bladed beta-propeller domains.
View Article and Find Full Text PDFAppl Environ Microbiol
December 2005
Two xyloglucan-specific endo-beta-1,4-glucanases (xyloglucanases [XEGs]), XEG5 and XEG74, with molecular masses of 40 kDa and 105 kDa, respectively, were isolated from the gram-positive bacterium Paenibacillus sp. strain KM21, which degrades tamarind seed xyloglucan. The genes encoding these XEGs were cloned and sequenced.
View Article and Find Full Text PDFOligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH; EC 3.2.1.
View Article and Find Full Text PDFA novel xyloglucan-specific endo-beta-1,4-glucanase (XEG), xyloglucanase, with a molecular mass of 80 kDa and a pI of 4.8, was isolated from the fungus Geotrichum sp. M128.
View Article and Find Full Text PDFA novel xyloglucan-specific exo-beta-glycosidase, oligoxyloglucan reducing-end specific cellobiohydrolase (OXG-RCBH), recognizes the reducing end of oligoxyloglucan and releases two glucosyl residue segments from the main chain. OXG-RCBH was crystallized by the hanging-drop vapour-diffusion method with polyethylene glycol 3000 and polyethylene glycol 400 as precipitants. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 61.
View Article and Find Full Text PDFA novel oligoxyloglucan-specific glycosidase, oligoxyloglucan reducing end-specific cellobiohydrolase (OXG-RCBH), with a molecular mass of 97 kDa and a pI of 6.1, was isolated from the fungus Geotrichum sp. M128.
View Article and Find Full Text PDFXyloglucan is a key polymer in the walls of growing plant cells. Using split pea stem segments and stem segments from which the epidermis had been peeled off, we demonstrate that the integration of xyloglucan mediated by the action of wall-bound xyloglucan endotransglycosylase suppressed cell elongation, whereas that of its fragment oligosaccharide accelerated it. Whole xyloglucan was incorporated into the cell wall and induced the rearrangement of cortical microtubules from transverse to longitudinal; in contrast, the oligosaccharide solubilized xyloglucan from the cell wall and maintained the microtubules in a transverse orientation.
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