Microbial Strategies for the Depolymerization of Glucuronoxylan: Leads to Biotechnological Applications of Endoxylanases

Preston, James F.; Hurlbert, Jason C.; Rice, John D.; Ragunathan, Anuradha; John, Franz J. St

doi:10.1021/bk-2003-0855.ch012

Cited by 23 publications

(47 citation statements)

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“…In contrast, GH5 enzymes do not have the GH30 characteristic conserved hinge regions and the sequences in the b1 and a8 terminal barrel motifs do not share obvious sequence similarities with the same regions of GH30 sequences. We observe that the a8 region of GH5 (b/a) 8 barrels show significant diversity (Fig. S8) within the GH5 family.…”

Section: Gh30 Unique Conserved Regionsmentioning

confidence: 87%

“…The overall structure of GH30 enzymes is unique in comparison to GH5 enzymes, being formed from the fusion of a common (b/a) 8 barrel CAZy designated Clan A catalytic module (4/7 hydrolase, GH5 like) [2,43] with a side b-structure consisting of a 9-stranded aligned b-sandwich, immunoglobulin like fold. This family-wide structural addition is hinged with conserved sequence from the N-and C-terminus regions [6,11].…”

Section: Side B-structure Rearrangementmentioning

confidence: 99%

“…2), almost identical phylogenetic tree distribution is produced from alignments that include only the sequence of the (b/a) 8 barrel rather than the complete dual domain structure. Several a-helical and loop regions within the (b/a) 8 barrel contribute to this differentiation. From the EXPRESSO structure guided alignment (Fig.…”

Section: Group Distinction Within the (B/a) 8 Barrelmentioning

confidence: 99%

“…From the EXPRES-SO alignment it is found that GH30 enzymes have a distinctive sequence conservation pattern. These include the two linker regions which connect the side b-structure to the (b/a) 8 catalytic center (Fig. 3a and d) and a continuous conserved region beginning with a-helix 3 and ending with the catalytic proton donor (Glu140 of XynC) positioned within b-strand 4 (Fig.…”

Section: Gh30 Unique Conserved Regionsmentioning

confidence: 99%

“…Recent biochemical characterization [4,5] and structural studies of the GH5 xylanase XynC from Bacillus subtilis [6] has directed attention to a previously noted inconsistency in the GH classification of this enzyme [7][8][9][10][11]. Early classification discussed the difficulty of making an unambiguous assignment based on hydrophobic cluster analysis comparisons with the XynC homolog, XynA from Erwinia chrysanthemi with GH family 5 and 30 (b/a) 8 barrel domains [12,13]. Within the current, more populated database space these enzymes show similarity to GH30 enzymes.…”

Section: Introductionmentioning

confidence: 99%

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Consolidation of glycosyl hydrolase family 30: A dual domain 4/7 hydrolase family consisting of two structurally distinct groups

2010

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Keywords:Glycosyl hydrolase family 30 (GH30) Glycosyl hydrolase family 5 (GH5) Glucuronoxylan xylanohydrolase Endo-b-1,6-galactanase Glucosylceramidase Endo-b-1,6-glucanase a b s t r a c tIn this work glycosyl hydrolase (GH) family 30 (GH30) is analyzed and shown to consist of its currently classified member sequences as well as several homologous sequence groups currently assigned within family GH5. A large scale amino acid sequence alignment and a phylogenetic tree were generated and GH30 groups and subgroups were designated. A partial rearrangement in the GH30 defining side-associated b-domain contributes to the differentiation of two major groups that contain up to eight subgroups. For this CAZy family of Clan A enzymes the dual domain fold is conserved, suggesting that it may be a requirement for evolved function. This work redefines GH family 30 and serves as a guide for future efforts regarding enzymes classified within this family.Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

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Section: Gh30 Unique Conserved Regionsmentioning

confidence: 87%

Section: Side B-structure Rearrangementmentioning

confidence: 99%

Section: Group Distinction Within the (B/a) 8 Barrelmentioning

confidence: 99%

Section: Gh30 Unique Conserved Regionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Consolidation of glycosyl hydrolase family 30: A dual domain 4/7 hydrolase family consisting of two structurally distinct groups

2010

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Production of acidic xylooligosaccharides from methylglucuronoarabinoxylans by Bacillus subtilis strain MR44

Rhee

Preston

et al. 2015

J of Chemical Tech & Biotech

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BACKGROUND Bacillus subtilis 168 secretes endoxylanases Xyn11A and Xyn30C and arabinofuranohydrolase Axh43 that process xylans in hemicellulose fractions. Engineered strain MR44 with a deletion in the xynA gene encoding Xyn11A, converts hardwood methylglucuronoxylans (MeGXn) of dicots to defined acidic xylooligosaccharides (U‐XOS) with a single methylglucuronate linked to xylooligosaccharides with an average ratio of one methylglucuronate to 6–7 xyloses as value‐added products. The MR44 strain also secretes Axh43 that catalyses release of arabinose from methylglucuronoarabinoxylans (MeGAXn) of monocots. RESULTS MR44 strain efficiently processes sorghum MeGAXn with 493 mg g−1 yields of purified U‐XOS. 1H‐NMR analysis of U‐XOS purified by anion exchange chromatography structurally defined the U‐XOS with an average degree of polymerization of xylose units (DP) of 11–12 and a single 4‐O‐methyl‐glucuronic acid α‐1,2‐linked on average to one of 11–12 xylose residues each penultimate to the reducing terminal xylose. CONCLUSION This study demonstrates the ability of Bacillus subtilis strains to process MeGAXn for production of U‐XOS from monocots, including energy crops and agricultural residues. The U‐XOS with an average DP of 11–12 from sweet sorghum MeGAXn compared with 6–7 from sweetgum MeGXn extends their applications as biologicals and for production of pentosan polysulfates with applications in human and veterinary medicine. © 2015 Society of Chemical Industry

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Metabolic potential of Bacillus subtilis 168 for the direct conversion of xylans to fermentation products

Rhee¹,

Sawhney

et al. 2015

Appl Microbiol Biotechnol

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Methylglucuronoxylans (MeGXn) and methylglucuronoarabinoxylans (MeGAXn) respectively comprise most of the hemicellulose fractions in dicots and monocots and, next to cellulose, are the major resources for the production of fuels and chemicals from lignocellulosics. With either MeGXn or MeGAXn as a substrate, Bacillus subtilis 168 accumulates acidic methylglucuronoxylotriose as a limit product following the uptake and metabolism of neutral xylooligosaccharides. Secreted GH11 endoxylanase (Xyn11A), GH30 endoxylanase (Xyn30C), and GH43 arabinoxylan arabinofuranohydrolase (Axh43) respectively encoded by the xynA, xynC, and xynD genes collectively contribute to the depolymerization of MeGAXn. Studies here demonstrate the complementary roles of these enzymes in the digestion of MeGAXn. Coordinate expression of the xynD and xynC genes defines an operon accounting for the Axh43-catalyzed release of arabinose followed by Xyn30C and Xyn11A-catalyzed depolymerization of MeGAXn. Both sources generate acetate and lactate as the principal fermentation products, with yields of 26 % acetate and 32 % lactate from MeGXn compared to 22 % acetate and 21 % lactate from MeGAXn. These studies of the GH43/GH30/GH11 system in B. subtilis 168 provide a basis for the further development of B. subtilis and related species as biocatalysts for direct conversion of hemicellulose derived from energy crops as well as agricultural and forest residues to chemical feedstocks.

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Microbial Strategies for the Depolymerization of Glucuronoxylan: Leads to Biotechnological Applications of Endoxylanases

Cited by 23 publications

References 0 publications

Consolidation of glycosyl hydrolase family 30: A dual domain 4/7 hydrolase family consisting of two structurally distinct groups

Consolidation of glycosyl hydrolase family 30: A dual domain 4/7 hydrolase family consisting of two structurally distinct groups

Production of acidic xylooligosaccharides from methylglucuronoarabinoxylans by Bacillus subtilis strain MR44

Metabolic potential of Bacillus subtilis 168 for the direct conversion of xylans to fermentation products

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