A Novel Multifunctional Arabinofuranosidase/Endo-xylanase/β-Xylosidase GH43 from Paenibacillus curdlanolyticus B-6 and Its Synergistic Action to Produce Arabinose and Xylose from Cereal Arabinoxylan

Author(s):  
Puangpen Limsakul ◽  
Paripok Phitsuwan ◽  
Rattiya Waeonukul ◽  
Patthra Pason ◽  
Chakrit Tachaapaikoon ◽  
...  

The PcAxy43B is a modular protein comprising a catalytic domain of glycoside hydrolase family 43 (GH43), a family 6 carbohydrate-binding module (CBM6) and a family 36 carbohydrate-binding module (CBM36) and found to be a novel multifunctional xylanolytic enzyme from Paenibacillus curdlanolyticus B-6. This enzyme exhibited α-L-arabinofuranosidase, endo-xylanase and β-D-xylosidase activities. α-L-Arabinofuranosidase of PcAxy43B revealed the new property of GH43, which released arabinose from the short-chain arabinoxylo-oligosaccharide (AXOS) and cereal arabinoxylan, and from both sides of the xylose residues of AXOS, which usually obstruct the action of xylanolytic enzymes. The PcAxy43B liberated series of xylo-oligosaccharides (XOSs) from birchwood xylan and xylohexaose, indicating that PcAxy43B exhibited endo-xylanase activity. The PcAxy43B produced xylose from xylobiose and reacted with p -nitrophenyl-β-D-xylopyranoside as a result of β-xylosidase activity. The PcAxy43B effectively released arabinose together with XOSs and xylose from the highly arabinosyl-substituted rye arabinoxylan. Moreover, PcAxy43B showed significant synergistic action with a trifunctional endo-xylanase/β-xylosidase/α-L-arabinofuranosidase PcAxy43A and an endo-xylanase Xyn10C from the strain B-6, in which almost all products produced from rye arabinoxylan by these combined enzymes were arabinose and xylose. In addition, the presence of CBM36 was found to be necessary for the endo-xylanase property of PcAxy43B. The PcAxy43B is capable of hydrolysing untreated cereal biomass, corn hull and rice straw into XOSs and xylose. Hence, PcAxy43B, the significant accessory multifunctional xylanolytic enzyme, is a potential candidate for application in the saccharification of cereal biomass. IMPORTANCE Enzymatic saccharification of cereal biomass is a strategy for the production of fermented sugars from low-price raw materials. In the present study, PcAxy43B from P. curdlanolyticus B-6 was found to be a novel multifunctional α-L-arabinofuranosidase/endo-xylanase/β-D-xylosidase enzyme of the glycoside hydrolase family 43. It is effective in releasing arabinose, xylose and XOSs from the highly arabinosyl-substituted rye arabinoxylan, which is usually resistant to hydrolysis by xylanolytic enzymes. Moreover, almost all products produced from rye arabinoxylan by the combination of PcAxy43B with trifunctional xylanolytic enzyme PcAxy43A and endo-xylanase Xyn10C from the strain B-6 were arabinose and xylose, which can be used to produce several value-added products. In addition, PcAxy43B is capable of hydrolysing untreated cereal biomass into XOSs and xylose. Thus, PcAxy43B is an important multifunctional xylanolytic enzyme with high potential in biotechnology.

2016 ◽  
Vol 82 (23) ◽  
pp. 6942-6951 ◽  
Author(s):  
Thitiporn Teeravivattanakit ◽  
Sirilak Baramee ◽  
Paripok Phitsuwan ◽  
Rattiya Waeonukul ◽  
Patthra Pason ◽  
...  

ABSTRACTTheaxy43Agene encoding the intracellular trifunctional xylanolytic enzyme fromPaenibacillus curdlanolyticusB-6 was cloned and expressed inEscherichia coli. Recombinant PcAxy43A consisting of a glycoside hydrolase family 43 and a family 6 carbohydrate-binding module exhibited endo-xylanase, β-xylosidase, and arabinoxylan arabinofuranohydrolase activities. PcAxy43A hydrolyzed xylohexaose and birch wood xylan to release a series of xylooligosaccharides, indicating that PcAxy43A contained endo-xylanase activity. PcAxy43A exhibited β-xylosidase activity toward a chromogenic substrate,p-nitrophenyl-β-d-xylopyranoside, and xylobiose, while it preferred to hydrolyze long-chain xylooligosaccharides rather than xylobiose. In addition, surprisingly, PcAxy43A showed arabinoxylan arabinofuranohydrolase activity; that is, it released arabinose from both singly and doubly arabinosylated xylose, α-l-Araf-(1→2)-d-Xylpor α-l-Araf-(1→3)-d-Xylpand α-l-Araf-(1→2)-[α-l-Araf-(1→3)]-β-d-Xylp. Moreover, the combination of PcAxy43A andP. curdlanolyticusB-6 endo-xylanase Xyn10C greatly improved the efficiency of xylose and arabinose production from the highly substituted rye arabinoxylan, suggesting that these two enzymes function synergistically to depolymerize arabinoxylan. Therefore, PcAxy43A has the potential for the saccharification of arabinoxylan into simple sugars for many applications.IMPORTANCEIn this study, the glycoside hydrolase 43 (GH43) intracellular multifunctional endo-xylanase, β-xylosidase, and arabinoxylan arabinofuranohydrolase (AXH) fromP. curdlanolyticusB-6 were characterized. Interestingly, PcAxy43A AXH showed a new property that acted on both the C(O)-2 and C(O)-3 positions of xylose residues doubly substituted with arabinosyl, which usually obstruct the action of xylanolytic enzymes. Furthermore, the studies here show interesting properties for the processing of xylans from cereal grains, particularly rye arabinoxylan, and show a novel relationship between PcAxy43A and endo-xylanase Xyn10C from strain B-6, providing novel metabolic potential for processing arabinoxylans into xylose and arabinose.


2009 ◽  
Vol 418 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Elien Vandermarliere ◽  
Tine M. Bourgois ◽  
Martyn D. Winn ◽  
Steven van Campenhout ◽  
Guido Volckaert ◽  
...  

AXHs (arabinoxylan arabinofuranohydrolases) are α-L-arabinofuranosidases that specifically hydrolyse the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. Bacillus subtilis was recently shown to produce an AXH that cleaves arabinose units from O-2- or O-3-mono-substituted xylose residues: BsAXH-m2,3 (B. subtilis AXH-m2,3). Crystallographic analysis reveals a two-domain structure for this enzyme: a catalytic domain displaying a five-bladed β-propeller fold characteristic of GH (glycoside hydrolase) family 43 and a CBM (carbohydrate-binding module) with a β-sandwich fold belonging to CBM family 6. Binding of substrate to BsAXH-m2,3 is largely based on hydrophobic stacking interactions, which probably allow the positional flexibility needed to hydrolyse both arabinose substituents at the O-2 or O-3 position of the xylose unit. Superposition of the BsAXH-m2,3 structure with known structures of the GH family 43 exo-acting enzymes, β-xylosidase and α-L-arabinanase, each in complex with their substrate, reveals a different orientation of the sugar backbone.


2021 ◽  
Author(s):  
Gregory S Bulmer ◽  
Fang Wei Yuen ◽  
Naimah Begum ◽  
Bethan S Jones ◽  
Sabine S Flitsch ◽  
...  

β-D-Galactofuranose (Galf) and its polysaccharides are found in bacteria, fungi and protozoa but do not occur in mammalian tissues, and thus represent a specific target for anti-pathogenic drugs. Understanding the enzymatic degradation of these polysaccharides is therefore of great interest, but the identity of fungal enzymes with exclusively galactofuranosidase activity has so far remained elusive. Here we describe the identification and characterization of a galactofuranosidase from the industrially important fungus Aspergillus niger. Phylogenetic analysis of glycoside hydrolase family 43 subfamily 34 (GH43_34) members revealed the occurrence of three distinct clusters and, by comparison with specificities of characterized bacterial members, suggested a basis for prediction of enzyme specificity. Using this rationale, in tandem with molecular docking, we identified a putative β-D-galactofuranosidase from A. niger which was recombinantly expressed in Escherichia coli. The Galf-specific hydrolase, encoded by xynD demonstrates maximum activity at pH 5, 25 °C towards 4-Nitrophenyl-β-galactofuranoside (pNP-βGalf), with a Km of 17.9 ± 1.9 mM and Vmax of 70.6 ± 5.3 μmol min-1. The characterization of this first fungal GH43 galactofuranosidase offers further molecular insight into the degradation of Galf-containing structures and may inform clinical treatments against fungal pathogens.


Author(s):  
Benjamin Pluvinage ◽  
Craig S. Robb ◽  
Roderick Jeffries ◽  
Alisdair B. Boraston

The recently identified marine bacterium Pseudoalteromonas fuliginea sp. PS47 possesses a polysaccharide-utilization locus dedicated to agarose degradation. In particular, it contains a gene (locus tag EU509_06755) encoding a β-agarase that belongs to glycoside hydrolase family 50 (GH50), PfGH50B. The 2.0 Å resolution X-ray crystal structure of PfGH50B reveals a rare complex multidomain fold that was found in two of the three previously determined GH50 structures. The structure comprises an N-terminal domain with a carbohydrate-binding module (CBM)-like fold fused to a C-terminal domain by a rigid linker. The CBM-like domain appears to function by extending the catalytic groove of the enzyme. Furthermore, the PfGH50B structure highlights key structural features in the mobile loops that may function to restrict the degree of polymerization of the neoagaro-oligosaccharide products and the enzyme processivity.


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