Release and characterization of single side chains of white cabbage pectin and their complement‐fixing activity

Westereng, Bjørge; Coenen, G.J.; Michaelsen, Terje E.; Voragen, A.G.J.; Samuelsen, Anne Berit; Schols, Henk A.; Knutsen, Svein Halvor

doi:10.1002/mnfr.200800199

Cited by 27 publications

(11 citation statements)

References 44 publications

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“…The positive control showed essentially the same profile as Pm23. nC, nanocoulomb; *, the corresponding sodium salt of sodium adducts often observed for carbohydrates containing carboxylic acids (30,43); RGI, rhamnogalacturonan I; AX, arabinoxylan; AGP, arabinogalactan protein; Xyl, xylooligosaccharide; MeGlcAXyl, 4-O-methylglucuronoxylooligosaccharide (aldouronic acid); n/a, not available. Details of probes used are provided in Table 2.…”

Section: Discussionmentioning

confidence: 99%

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A New Versatile Microarray-based Method for High Throughput Screening of Carbohydrate-active Enzymes

Vidal‐Melgosa

Pedersen

Schückel

et al. 2015

Journal of Biological Chemistry

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Background: There is a growing discrepancy between the putative identification and the empirical characterization of carbohydrate-active enzymes (CAZymes). Results: We have developed a new versatile and high throughput microarray-based method for screening CAZymes. Conclusion:The method is a powerful addition to the enzyme screening toolbox. Significance: The technique enables the rapid screening of CAZymes and facilitates our biological understanding and industrial utilization.

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Section: Discussionmentioning

confidence: 99%

“…MS was conducted essentially as described (30) except that Dowex 50 treatment and sodium chloride doping were omitted. HPAEC was run as described previously (31).…”

Section: Validation Of Specificities By Matrix-assisted Laser Desorptmentioning

confidence: 99%

A New Versatile Microarray-based Method for High Throughput Screening of Carbohydrate-active Enzymes

Vidal‐Melgosa

Pedersen

Schückel

et al. 2015

Journal of Biological Chemistry

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“…All ion clusters have a similar adduct distribution as shown for the DP5 cluster in the zoom in picture to the right; notably, after lithium doping Na and K-adducts are no longer present. The presence of double adducts, as seen in panels A and B, is indicative of the presence of a carboxyl group as in an aldonic acid 51 . The reaction conditions were: 1.5% (w/v) PASC, 1μM Tt LPMO9E, 25 mM Bis-Tris pH 6.5, 2 mM ascorbic acid, incubation for three days at 50 °C, at 1000 rpm.…”

Section: Figurementioning

confidence: 95%

Enzymatic cellulose oxidation is linked to lignin by long-range electron transfer

Westereng

Cannella

Agger

et al. 2015

Sci Rep

189

169

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While it has been known for decades that enzymatic oxidation of lignin by laccases and peroxidases plays a role in microbial biomass conversion of lignin, it has only very recently become apparent that oxidative processes also play a major role in the conversion of polysaccharides. The latter process is carried out by so-called Lytic Polysaccharide MonoOxygenases (LPMOs) 1 , which are copper-dependent enzymes capable of breaking glycosidic bonds in polysaccharides, such as cellulose, xyloglucan, glucomannan, xylan, starch and chitin 2-9 . LPMO activity depends on the presence of molecular oxygen and requires an electron donor. So far, it has been shown that electrons can be provided by cellobiose dehydrogenase (CDH) 10 or by small molecule electron donors such as ascorbic acid 7 or gallic acid 6 . However, virtually nothing is known about how the LPMO-catalyzed redox reactions and electron transfers function within the plant cell wall matrix during biological decay.During biomass conversion by fungi, many of the lignin-and carbohydrate-active redox enzymes are expressed simultaneously with hydrolytic enzymes 11,12 , which points to a possible interplay between these enzyme systems. LPMO-encoding genes are abundant in the genomes of biomass degrading and plant pathogenic fungi, and when grown on lignocellulosic material, LPMOs are among the most highly expressed proteins [13][14][15][16] . Notably, there is ample evidence that LPMOs enhance the power of the fungal degradative enzyme machinery 17,18 . Today, LPMOs are important components in industrial enzyme cocktails used for saccharification of cellulosic biofuel feedstocks 19,20 .LPMOs are copper enzymes 6 , which cycle between Cu (I) and Cu (II) to activate molecular oxygen. Kim et al. (2014) suggested a mechanism involving the formation of a copper-oxyl radical that abstracts a hydrogen and then hydroxylates the substrate via an oxygen-rebound mechanism 21 . The details of oxygen activation were further elaborated by X-ray absorption studies of the active site copper, leading to the conclusion that the initial oxygen species is a super oxide 22 . During in vivo conditions, the electron donor may be CDH, but microorganisms may also utilize other approaches for providing electron donors to oxidative reactions. Lignin is one of the main structural components in plants and has an electron configuration that provides a low barrier for electron transfer. There are indications that lignin may act as electron donor for LPMOs 18,23 , but substantial evidence is scarce.One-electron transfer from lignin, proceeding via an outer sphere mechanism 24 , is well known and has been described for lignin oxidizing enzymes such as laccases 25 . The transfer may take place through direct interactions

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“…Nine different substrates were used: phosphoric acid swollen cellulose (PASC), birchwood xylan, wheat arabinoxylan, aspen xylan, ivory nut mannan, carob galactomannan, konjac glucomannan, tamarind xyloglucan and pectin. PASC from Avicel, pectin from white cabbage and aspen xylan (isolated under mild conditions to avoid autohydrolysis of the acetyl groups during the isolation process (Biely et al, 2013)) were prepared as described earlier (Wood, 1988;Westereng et al, 2009;Biely et al, 2013), birchwood xylan was purchased from Roth (Karlsruhe, Germany) and all other substrates were purchased from Megazyme (Wicklow, Ireland). Enzyme reactions were performed overnight at 408C and supernatants containing soluble products were collected by centrifugation at 16 600 3 g for three minutes.…”

Section: Enzymatic Assays and Pgc-ms Analysismentioning

confidence: 99%

Outer membrane vesicles from Fibrobacter succinogenes S85 contain an array of carbohydrate‐active enzymes with versatile polysaccharide‐degrading capacity

Arntzen

Várnai

Mackie

et al. 2017

Environmental Microbiology

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Fibrobacter succinogenes is an anaerobic bacterium naturally colonising the rumen and cecum of herbivores where it utilizes an enigmatic mechanism to deconstruct cellulose into cellobiose and glucose, which serve as carbon sources for growth. Here, we illustrate that outer membrane vesicles (OMVs) released by F. succinogenes are enriched with carbohydrate-active enzymes and that intact OMVs were able to depolymerize a broad range of linear and branched hemicelluloses and pectin, despite the inability of F. succinogenes to utilize non-cellulosic (pentose) sugars for growth. We hypothesize that the degradative versatility of F. succinogenes OMVs is used to prime hydrolysis by destabilising the tight networks of polysaccharides intertwining cellulose in the plant cell wall, thus increasing accessibility of the target substrate for the host cell. This is supported by observations that OMV-pretreatment of the natural complex substrate switchgrass increased the catalytic efficiency of a commercial cellulose-degrading enzyme cocktail by 2.4-fold. We also show that the OMVs contain a putative multiprotein complex, including the fibro-slime protein previously found to be important in binding to crystalline cellulose. We hypothesize that this complex has a function in plant cell wall degradation, either by catalysing polysaccharide degradation itself, or by targeting the vesicles to plant biomass.

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Release and characterization of single side chains of white cabbage pectin and their complement‐fixing activity

Cited by 27 publications

References 44 publications

A New Versatile Microarray-based Method for High Throughput Screening of Carbohydrate-active Enzymes

A New Versatile Microarray-based Method for High Throughput Screening of Carbohydrate-active Enzymes

Enzymatic cellulose oxidation is linked to lignin by long-range electron transfer

Outer membrane vesicles from Fibrobacter succinogenes S85 contain an array of carbohydrate‐active enzymes with versatile polysaccharide‐degrading capacity

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