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Characterization and pH-dependent substrate specificity of alkalophilic xylanase from Bacillus alcalophilus. J Ind Microbiol Biotechnol 2012; 39:1465-75. [PMID: 22763748 DOI: 10.1007/s10295-012-1159-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/11/2012] [Indexed: 10/28/2022]
Abstract
The gene of endo-beta-1-4 xylanase, xynT, was cloned from Bacillus alcalophilus AX2000 and expressed in Escherichia coli. This XynT, which belongs to glycoside hydrolase (GH) family 10, was found to have a molecular weight of approximately 37 kDa and exhibit optimal activity at pH 7-9 and 50 °C. It exhibits a high activity towards birchwood xylan and has the ability to bind avicel. Under optimal conditions, XynT hydrolyzes all xylooligomers into xylobiose as an end product with a preference for cleavage sites at the second or third glycosidic bond from the reducing end. XynT has a different substrate affinity on xylooligomers at pH 5.0, which contributes to its low activity toward xylotriose and its derived intermediate products. This low activity may be due to an unstable interaction with the amino acids that constitute subsites of the active site. Interestingly, the addition of Co(2+) and Mn(2+) led to a significant increase in activity by up to 40 and 50 %, respectively. XynT possesses a high binding affinity and hydrolytic activity toward the insoluble xylan, for which it exhibits high activity at pH 7-9, giving rise to its efficient biobleaching effect on Pinus densiflora kraft pulp.
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Kongsted J, Ryde U, Wydra J, Jensen JH. Prediction and Rationalization of the pH Dependence of the Activity and Stability of Family 11 Xylanases. Biochemistry 2007; 46:13581-92. [DOI: 10.1021/bi7016365] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jacob Kongsted
- Department of Theoretical Chemistry, Chemical Center, University of Lund, S221 00 Lund, Sweden, Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Ulf Ryde
- Department of Theoretical Chemistry, Chemical Center, University of Lund, S221 00 Lund, Sweden, Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - James Wydra
- Department of Theoretical Chemistry, Chemical Center, University of Lund, S221 00 Lund, Sweden, Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Jan H. Jensen
- Department of Theoretical Chemistry, Chemical Center, University of Lund, S221 00 Lund, Sweden, Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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Honda Y, Kitaoka M. A family 8 glycoside hydrolase from Bacillus halodurans C-125 (BH2105) is a reducing end xylose-releasing exo-oligoxylanase. J Biol Chem 2004; 279:55097-103. [PMID: 15491996 DOI: 10.1074/jbc.m409832200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding family 8 glycoside hydrolases from Bacillus halodurans C-125 (BH2105), an alkalophilic bacterium with a known genomic sequence, was expressed in Escherichia coli. The protein was expressed with the intact N-terminal sequence, suggesting that it did not possess a signal peptide and that it was an intracellular enzyme. The recombinant enzyme showed no hydrolytic activity on xylan, whereas it had been annotated as xylanase Y. It hydrolyzed xylooligosaccharide whose degree of polymerization is greater than or equal to 3 in an exo-splitting manner with anomeric inversion, releasing the xylose unit at the reducing end. Judging from its substrate specificity and reaction mechanism, we named the enzyme reducing end xylose-releasing exo-oligoxylanase (Rex). Rex was found to utilize only the beta-anomer of the substrate to form beta-xylose and alpha-xylooligosaccharide. The optimum pH of the enzymatic reaction (6.2-7.3) was found in the neutral range, a range beneficial for intracellular enzymes. The genomic sequence suggests that B. halodurans secretes two endoxylanases and possesses two alpha-arabinofuranosidases, one alpha-glucuronidase, and three beta-xylosidases intracellularly in addition to Rex. The extracellular enzymes supposedly hydrolyze xylan into arabino/glucurono-xylooligosaccharides that are then transported into the cells. Rex may play a role as a key enzyme in intracellular xylan metabolism in B. halodurans by cleaving xylooligosaccharides that were produced by the action of other intracellular enzymes from the arabino/glucurono-xylooligosaccharides.
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Affiliation(s)
- Yuji Honda
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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Goesaert H, Elliott G, Kroon PA, Gebruers K, Courtin CM, Robben J, Delcour JA, Juge N. Occurrence of proteinaceous endoxylanase inhibitors in cereals. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1696:193-202. [PMID: 14871660 DOI: 10.1016/j.bbapap.2003.08.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2003] [Accepted: 08/07/2003] [Indexed: 11/20/2022]
Abstract
Cereals contain proteinaceous inhibitors of endoxylanases, which affect the efficiency and functionality of these enzymes in cereal processing. This review relates their first discovery in wheat and the subsequent purification of two distinct classes of endoxylanase inhibitors, namely Triticum aestivum xylanase inhibitor (TAXI)-type and xylanase inhibitor protein (XIP)-type inhibitors in cereals. Both inhibitor classes occur in monocots as multi-isoform families. The reported data provide an overview of the relative quantitative and qualitative variation of these inhibitors in cereals. Wheat and rye are particularly rich in TAXI-type and XIP-type inhibitors with the latter inhibitors being more abundant. Lower inhibitor levels are present in durum wheat and barley, while maize contains solely XIP-type inhibitors. No inhibitors have been isolated from rice, oats and buckwheat.
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Affiliation(s)
- Hans Goesaert
- KU Leuven, Laboratory of Food Chemistry, Kasteelpark Arenberg 20, B-3001 Louvain, Belgium.
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Shintate K, Kitaoka M, Kim YK, Hayashi K. Enzymatic synthesis of a library of β-(1→4) hetero- d-glucose and d-xylose-based oligosaccharides employing cellodextrin phosphorylase. Carbohydr Res 2003; 338:1981-90. [PMID: 14499574 DOI: 10.1016/s0008-6215(03)00314-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Enzymatic synthesis was attempted of six trisaccharides and 14 tetrasaccharides comprising beta-(1-->4)-linked D-glucose and D-xylose residues, using cellodextrin phosphorylase (CDP, EC 2.4.1.49) as the enzyme catalyst, with alpha-D-glucose 1-phosphate (1) or alpha-D-xylose 1-phosphate (2) as the donor substrates, and cellobiose (3), xylobiose (4), betaGlc-(1-->4)-Xyl (5), or betaXyl-(1-->4)-Glc (6) as the acceptor substrates. All enzymatic reactions were performed at pH 7.0 and the products purified by gel-filtration chromatography. We successfully synthesized all six hetero-trisaccharides and 10 of the 14 possible hetero-tetrasaccharides. It was not found possible to synthesize the four tetrasaccharides with a Xyl-->Glc sequence at their non-reducing ends employing this method. The stereochemistries of the isolated products were assessed by analysis of their 2D NMR spectra (DQF-COSY, TOCSY, HSQC, HMBC), confirming that all of the glycosidic bonds in the products were beta-(1-->4) linkages.
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Affiliation(s)
- Keiko Shintate
- Enzyme Laboratory, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
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Nishimoto M, Honda Y, Kitaoka M, Hayashi K. A kinetic study on pH-activity relationship of XynA from alkaliphilic Bacillus halodurans C-125 using aryl-xylobiosides. J Biosci Bioeng 2002; 93:428-30. [PMID: 16233226 DOI: 10.1016/s1389-1723(02)80079-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2001] [Accepted: 12/27/2001] [Indexed: 10/27/2022]
Abstract
Xylanase A from alkaliphilic Bacillus halodurans C-125 was expressed in Escherichia coli and purified by affinity and anion exchange chromatographies. It exhibited a strong substrate inhibition using xylan as the substrate. Its K(i) value increased with an increase in pH. The effect of pH on the enzyme activity was determined using two aryl-xylobiosides as substrates, and it was found that the enzyme had a flat k(cat)-pH curve in the pH range of 5.8-8.8. This range was different from that obtained with 0.45% xylan as previously reported (Honda, H. et al., Agric. Biol. Chem., 49, 3165-3169, 1985). The substrate inhibition was presumed to cause the difference. It has been clarified that the use of aryl-xylobiosides as substrates yields more accurate kinetic results than that of xylan.
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Affiliation(s)
- Mamoru Nishimoto
- Enzyme Laboratory, National Food Research Institute, Kannondai, Ibaraki 305-8642, Japan
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Employing chimeric xylanases to identify regions of an alkaline xylanase participating in enzyme activity at basic pH. J Biosci Bioeng 2002. [DOI: 10.1016/s1389-1723(02)80215-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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