(4-O-Methyl-α-d-glucurono)-d-xylan from Rudbeckia fulgida, var. sullivantii (Boynton et Beadle)

Kardošová, Alžbeta; Matulovà, Maria; Malovı́ková, Anna

doi:10.1016/s0008-6215(98)00072-x

Cited by 54 publications

(40 citation statements)

References 17 publications

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“…Analysis of the YM-3 filtrate fraction by 1 H NMR (Fig. 3A) yielded the expected distribution of peaks based on previous proton shift assignments for similar xylooligomers substituted with methylglucuronosyl residues (8,15,30). The integration ratio of the signals for the proton on carbon five of the MeGA, the proton on carbon five of the nonreducing xylose, and the proton on carbon one of the reducing xylose (␣ and ␤ configurations) was 1.0:1.1:0.9, establishing that the products of XynC depolymerization contained a single MeGA moiety ␣-1,2 linked to ␤-1,4-xylooligosaccharides.…”

Section: Resultssupporting

confidence: 57%

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Characterization of XynC from Bacillus subtilis subsp. subtilis Strain 168 and Analysis of Its Role in Depolymerization of Glucuronoxylan

2006

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Secretion of xylanase activities by Bacillus subtilis 168 supports the development of this well-defined genetic system for conversion of methylglucuronoxylan (MeGAX n [where n represents the number of xylose residues]) in the hemicellulose component of lignocellulosics to biobased products. In addition to the characterized glycosyl hydrolase family 11 (GH 11) endoxylanase designated XynA, B. subtilis 168 secretes a second endoxylanase as the translated product of the ynfF gene. This sequence shows remarkable homology to the GH 5 endoxylanase secreted by strains of Erwinia chrysanthemi. To determine its properties and potential role in the depolymerization of MeGAX n , the ynfF gene was cloned and overexpressed to provide an endoxylanase, designated XynC, which was characterized with respect to substrate preference, kinetic properties, and product formation. With different sources of MeGAX n as the substrate, the specific activity increased with increasing methylglucuronosyl substitutions on the ␤-1,4-xylan chain. With MeGAX n from sweetgum as a preferred substrate, XynC exhibited a V max of 59.9 units/mg XynC, a K m of 1.63 mg MeGAX n /ml, and a k cat of 2,635/minute at pH 6.0 and 37°C. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and 1 H nuclear magnetic resonance data revealed that each hydrolysis product has a single glucuronosyl substitution penultimate to the reducing terminal xylose. This detailed analysis of XynC from B. subtilis 168 defines the unique depolymerization process catalyzed by the GH 5 endoxylanases. Based upon product analysis, B. subtilis 168 secretes both XynA and XynC. Expression of xynA was subject to MeGAX n induction; xynC expression was constitutive with growth on different substrates. Translation and secretion of both GH 11 and GH 5 endoxylanases by the fully sequenced and genetically malleable B. subtilis 168 recommends this bacterium for the introduction of genes required for the complete utilization of products of the enzymecatalyzed depolymerization of MeGAX n . B. subtilis may serve as a model platform for development of grampositive biocatalysts for conversion of lignocellulosic materials to renewable fuels and chemicals.

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Section: Resultssupporting

confidence: 57%

“…MeGAX n was isolated from sweetgum wood as previously described (29) and characterized by 13 C NMR (30). Birch and beech wood xylans were obtained from Sigma-Aldrich.…”

Section: Methodsmentioning

confidence: 99%

Characterization of XynC from Bacillus subtilis subsp. subtilis Strain 168 and Analysis of Its Role in Depolymerization of Glucuronoxylan

2006

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“…The solution was incubated under the initial conditions for another 24 h, whereupon the concentration procedure was performed again, resulting in another set of filtrate (filtrate 2) and retentate (retentate 2) fractions. All four fractions were lyophilized and subjected to matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrographic analysis (26) and 13 C-NMR analysis as previously described (19). To determine the position of the 4-O-methyl-glucuronic acid-substituted xylose residue in the xylosaccharide products, filtrates 1 and 2 were incubated in the presence of ␤-xylosidase isolated from Aspergillus niger (Sigma Chemical).…”

Section: Methodsmentioning

confidence: 99%

Functional Characterization of a Novel Xylanase from a Corn Strain of Erwinia chrysanthemi

Hurlbert

Preston

2001

J Bacteriol

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A ␤-1,4-xylan hydrolase (xylanase A) produced by Erwinia chrysanthemi D1 isolated from corn was analyzed with respect to its secondary structure and enzymatic function. The pH and temperature optima for the enzyme were found to be pH 6.0 and 35°C, with a secondary structure under those conditions that consists of approximately 10 to 15% ␣-helices. The enzyme was still active at temperatures higher than 40°C and at pHs of up to 9.0. The loss of enzymatic activity at temperatures above 45°C was accompanied by significant loss of secondary structure. The enzyme was most active on xylan substrates with low ratios of xylose to 4-O-methyl-D-glucuronic acid and appears to require two 4-O-methyl-D-glucuronic acid residues for substrate recognition and/or cleavage of a ␤-1,4-xylosidic bond. The enzyme hydrolyzed sweetgum xylan, generating products with a 4-O-methyl-glucuronic acid-substituted xylose residue one position from the nonreducing terminus of the oligoxyloside product. No internal cleavages of the xylan backbone between substituted xylose residues were observed, giving the enzyme a unique mode of action in the hydrolysis compared to all other xylanases that have been described. Given the size of the oligoxyloside products generated by the enzyme during depolymerization of xylan substrates, the function of the enzyme may be to render substrate available for other depolymerizing enzymes instead of producing oligoxylosides for cellular metabolism and may serve to produce elicitors during the initiation of the infectious process.

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“…Enzymic studies on the distribution of4-0-methylglucuronic acid residues in glucuronoxylan from sunflower hulls indicated a regular pattern (Bazus et at., 1992). Similarly, a regular distribution pattern was established by a physical method for the 4-0-methylglucuronoxylans of the herbal plants Althaea officillalis (Kardosova, 1990) and Rudbeckia fulgida (Kardosova et aL, 1998). This is in contrast to a rather blockwise distribution suggested for hardwood glucuronoxylans (Kohn et al~1985).…”

Section: Structural Featuresmentioning

confidence: 97%

Xylans of Industrial and Biomedical Importance

Ebringerová

Hromàdková

1999

Biotechnology and Genetic Engineering Reviews

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(4-O-Methyl-α-d-glucurono)-d-xylan from Rudbeckia fulgida, var. sullivantii (Boynton et Beadle)

Cited by 54 publications

References 17 publications

Characterization of XynC from Bacillus subtilis subsp. subtilis Strain 168 and Analysis of Its Role in Depolymerization of Glucuronoxylan

Characterization of XynC from Bacillus subtilis subsp. subtilis Strain 168 and Analysis of Its Role in Depolymerization of Glucuronoxylan

Functional Characterization of a Novel Xylanase from a Corn Strain of Erwinia chrysanthemi

Xylans of Industrial and Biomedical Importance

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