B-d-Xylosidase from Selenomonas ruminantium: Catalyzed Reactions with Natural and Artificial Substrates

Jordan, Douglas B.

doi:10.1007/978-1-60327-526-2_27

Cited by 5 publications

(8 citation statements)

References 16 publications

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“…The Selenomonades group was dominated by (1030 reads) and (817 reads) that annotated to rumen‐associated Selenomonas ruminantium and Phascolarctobacterium faecium , respectively. Selenomonas ruminantium is known for its ability to produce β‐xylosidases (family GH43), effective catalysts for xylo‐oligosaccharide hydrolysis (Jordan ).…”

Section: Discussionmentioning

confidence: 99%

The hindgut lumen prokaryotic microbiota of the termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

et al. 2013

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Reticulitermes flavipes (Isoptera: Rhinotermitidae) is a highly eusocial insect that thrives on recalcitrant lignocellulosic diets through nutritional symbioses with gut-dwelling prokaryotes and eukaryotes. In the R. flavipes hindgut, there are up to 12 eukaryotic protozoan symbionts; the number of prokaryotic symbionts has been estimated in the hundreds. Despite its biological relevance, this diverse community, to date, has been investigated only by culture- and cloning-dependent methods. Moreover, it is unclear how termite gut microbiomes respond to diet changes and what roles they play in lignocellulose digestion. This study utilized high-throughput 454 pyrosequencing of 16S V5-V6 amplicons to sample the hindgut lumen prokaryotic microbiota of R. flavipes and to examine compositional changes in response to lignin-rich and lignin-poor cellulose diets after a 7-day feeding period. Of the ~475,000 high-quality reads that were obtained, 99.9% were annotated as bacteria and 0.11% as archaea. Major bacterial phyla included Spirochaetes (24.9%), Elusimicrobia (19.8%), Firmicutes (17.8%), Bacteroidetes (14.1%), Proteobacteria (11.4%), Fibrobacteres (5.8%), Verrucomicrobia (2.0%), Actinobacteria (1.4%) and Tenericutes (1.3%). The R. flavipes hindgut lumen prokaryotic microbiota was found to contain over 4761 species-level phylotypes. However, diet-dependent shifts were not statistically significant or uniform across colonies, suggesting significant environmental and/or host genetic impacts on colony-level microbiome composition. These results provide insights into termite gut microbiome diversity and suggest that (i) the prokaryotic gut microbiota is much more complex than previously estimated, and (ii) environment, founding reproductive pair effects and/or host genetics influence microbiome composition.

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Section: Discussionmentioning

confidence: 99%

The hindgut lumen prokaryotic microbiota of the termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

et al. 2013

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“…For example, if v/E T values are calculated by substituting the kinetic parameters of wild-type SXA, W145F, W145L, and W145Y into Eq. (5) with D-xylose set at 100 mM and X2 set at 100 mM, then v/E T values of W145F, W145L, and analyzed for D-xylose by HPLC with pulsed amperometric detection as described [19]. Observed concentrations of D-xylose are plotted (hollow circles for wild-type SXA and filled circles for W145 mutants).…”

Section: Resultsmentioning

confidence: 99%

“…Its k cat and k cat /K m are at least tenfold greater than those reported for other b-xylosidases [16,19,23] when acting on oligoxylosides of increasing degrees of polymerization from xylobiose (DP2) to xylohexaose (DP6). Its strength of catalysis [16,19,23], good stability versus moderately low pH (stable above pH 4.0) and temperature (stable below 50°C) [15], and ease of protein production in Escherichia coli (30% of soluble cell protein is SXA with greater than 5 g SXA produced per liter of culture under nonoptimized conditions) [14] recommend employment of SXA in industrial processes where it would serve in the hydrolysis of herbaceous biomass (xylan fraction) to simple sugars for fermentation to fuel ethanol and other bioproducts [11,33]. SXA belongs to glycoside hydrolase family 43 (GH43) and structural clan F of the CAZy database (Carbohydrate Active Enzymes database, http://www.cazy.org/) [4,12].…”

Section: Introductionmentioning

confidence: 88%

“…Substrates, buffers, and other reagents [7,17,21,22], circular dichroism spectroscopy [17], HPLC with pulsed amperometric detection [19], isothermal calorimetry [21], SDS-PAGE analysis [15], UV-V is spectroscopy [17], and molecular modeling [7] have been described. D-Xylobiose (X2) was obtained from Wako Chemicals USA (Richmond, VA).…”

Section: Materials and General Methodsmentioning

confidence: 99%

“…SXA has the simplest active site possible for an efficient glycoside hydrolase by comprising only two subsites [3], subsite -1 for binding the substrate glycone and subsite ?1 for binding the substrate aglycone. Because the simplicity of SXA lends itself to study, and because of the potential practical importance of SXA, a good deal has been learned about its structure-function properties [3,[16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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Engineering lower inhibitor affinities in β-d-xylosidase of Selenomonas ruminantium by site-directed mutagenesis of Trp145

Jordan

Wagschal

Fan

et al. 2011

J Ind Microbiol Biotechnol

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β-D-Xylosidase/α-L-arabinofuranosidase from Selenomonas ruminantium is the most active enzyme reported for catalyzing hydrolysis of 1,4-β-D-xylooligosaccharides to D-xylose. One property that could use improvement is its relatively high affinities for D-glucose and D-xylose (K (i) ~ 10 mM), which would impede its performance as a catalyst in the saccharification of lignocellulosic biomass for the production of biofuels and other value-added products. Previously, we discovered that the W145G variant expresses K(i)(D-glucose) and K(i)(D-xylose) twofold and threefold those of the wild-type enzyme. However, in comparison to the wild type, the variant expresses 11% lower k(cat)(D-xylobiose) and much lower stabilities to temperature and pH. Here, we performed saturation mutagenesis of W145 and discovered that the variants express K (i) values that are 1.5-2.7-fold (D-glucose) and 1.9-4.6-fold (D-xylose) those of wild-type enzyme. W145F, W145L, and W145Y express good stability and, respectively, 11, 6, and 1% higher k(cat)(D-xylobiose) than that of the wild type. At 0.1 M D-xylobiose and 0.1 M D-xylose, kinetic parameters indicate that W145F, W145L, and W145Y catalytic activities are respectively 46, 71, and 48% greater than that of the wild-type enzyme.

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β-xylosidase from Selenomonas ruminantium: Immobilization, stabilization, and application for xylooligosaccharide hydrolysis

Terrasan

Aragon

Masui

et al. 2016

Biocatalysis and Biotransformation

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The tetrameric b-xylosidase from Selenomonas ruminantium is very stable in alkaline pH allowing it to easily immobilize by multipoint covalent attachments on highly activated glyoxyl agarose gels. Initial immobilization resulted only in slight stabilization in relation to the free enzyme, since involvement of all subunits was not achieved. Coating the catalyst with aldehydedextran or polyethylenimine, fully stabilized the quaternary structure of the enzyme rendering much more stabilization to the biocatalyst. The catalyst coated with polyethylenimine of molecular weight 1300 is the most stable one exhibiting an interesting half-life of more than 10 days at pH 5.0 and 50 C, being, therefore, 240-fold more stable than free enzyme. Optimum activity was observed in the pH range 4.0-6.0 and at 55 C. The catalyst retained its side activity against p-nitrophenyl a-Larabinofuranoside and it was inhibited by xylose and glucose. Kinetic parameters with p-nitrophenyl b-D-xylopyranoside as substrate were V max 0.20 mmol.min À1 mg prot. À1 , K m 0.45 mM, K cat 0.82 s À1 , and K cat /K m 1.82 s À1 mM À1. Xylose release was observed from the hydrolysis of xylooligosaccharides with a decrease in the rate of xylose release by increasing substrate chainlength. Due to the high thermostability and the complete stability after five reuse cycles, the applicability of this biocatalyst in biotechnological processes, such as for the degradation of lignocellulosic biomass, is highly increased.

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B-d-Xylosidase from Selenomonas ruminantium: Catalyzed Reactions with Natural and Artificial Substrates

Cited by 5 publications

References 16 publications

The hindgut lumen prokaryotic microbiota of the termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

The hindgut lumen prokaryotic microbiota of the termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

Engineering lower inhibitor affinities in β-d-xylosidase of Selenomonas ruminantium by site-directed mutagenesis of Trp145

β-xylosidase from Selenomonas ruminantium: Immobilization, stabilization, and application for xylooligosaccharide hydrolysis

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