<i>Fg</i><scp>LPMO</scp>9A from <i>Fusarium graminearum</i> cleaves xyloglucan independently of the backbone substitution pattern

Nekiunaite, Laura; Petrović, Dejan M.; Westereng, Bjørge; Vaaje‐Kolstad, Gustav; Hachem, Maher Abou; Várnai, Anikó; Eijsink, Vincent G. H.

doi:10.1002/1873-3468.12385

Cited by 48 publications

(39 citation statements)

References 44 publications

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“…As expected on the basis of previously published data, Ta LPMO9A showed a mixed C1/C4‐oxidizing activity on PASC, with the C4‐oxidizing activity being dominating. Importantly, we show that Ta LPMO9A is also able to cleave xyloglucan and that cleavage likely can happen independent of the backbone substitution pattern, similar to Fg LPMO9A and Gt LPMO9A‐2 . Interestingly, the MALDI‐TOF MS data shown in Supporting Information Figure S7B may indicate production of a double‐oxidized xyloglucan fragment, which has also been observed for Fg LPMO9A and which would unambiguously proof that LPMOs can cleave xyloglucan at both C1 and C4 positions.…”

Section: Discussionmentioning

confidence: 69%

“…Importantly, we show that Ta LPMO9A is also able to cleave xyloglucan and that cleavage likely can happen independent of the backbone substitution pattern, similar to Fg LPMO9A and Gt LPMO9A‐2 . Interestingly, the MALDI‐TOF MS data shown in Supporting Information Figure S7B may indicate production of a double‐oxidized xyloglucan fragment, which has also been observed for Fg LPMO9A and which would unambiguously proof that LPMOs can cleave xyloglucan at both C1 and C4 positions. Further analytical work is needed to finally proof the formation of such fragments.…”

Section: Discussionmentioning

confidence: 69%

“…(A) HPAEC‐PAD profiles showing products released from PASC. Oxidized products are indicated in the figure and assignments of these peaks were based on the previous work . Native products elute prior to the C1‐oxidized products.…”

Section: Resultsmentioning

confidence: 99%

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Methylation of the N‐terminal histidine protects a lytic polysaccharide monooxygenase from auto‐oxidative inactivation

et al. 2018

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The catalytically crucial N-terminal histidine (His1) of fungal lytic polysaccharide monooxygenases (LPMOs) is post-translationally modified to carry a methylation. The functional role of this methylation remains unknown. We have carried out an in-depth functional comparison of two variants of a family AA9 LPMO from Thermoascus aurantiacus (TaLPMO9A), one with, and one without the methylation on His1. Various activity assays showed that the two enzyme variants are identical in terms of substrate preferences, cleavage specificities and the ability to activate molecular oxygen. During the course of this work, new functional features of TaLPMO9A were discovered, in particular the ability to cleave xyloglucan, and these features were identical for both variants. Using a variety of techniques, we further found that methylation has minimal effects on the pK of His1, the affinity for copper and the redox potential of bound copper. The two LPMOs did, however, show clear differences in their resistance against oxidative damage. Studies with added hydrogen peroxide confirmed recent claims that low concentrations of H O boost LPMO activity, whereas excess H O leads to LPMO inactivation. The methylated variant of TaLPMO9A, produced in Aspergillus oryzae, was more resistant to excess H O and showed better process performance when using conditions that promote generation of reactive-oxygen species. LPMOs need to protect themselves from reactive oxygen species generated in their active sites and this study shows that methylation of the fully conserved N-terminal histidine provides such protection.

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 69%

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Methylation of the N‐terminal histidine protects a lytic polysaccharide monooxygenase from auto‐oxidative inactivation

et al. 2018

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“…The occurrence of xyloglucan oligosaccharides carrying less than three pentose units (most likely xylosyl substitutions) indicates cleavage of the xyloglucan backbone between two substituted glucosyl units. This unique cleavage pattern has only been shown for a handful of enzymes belonging to the GH74 and AA9 families so far (Desmet et al ., ; Feng et al ., ; Kojima et al ., ; Nekiunaite et al ., ) and could potentially be attributed to FSU_2866, an OMV protein annotated as a BNR repeat protein and predicted to harbour four GH74 modules (Supporting Information Table S1).…”

Section: Resultsmentioning

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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“…Recently, other fungal AA9 LPMOs have been shown to catalyze oxidative cleavage of cellulose and xyloglucan. They originate from the ascomycetes Asperillus niger (AN3046) [25] and Fusarium graminearum ( Fg LPMO9A) [26] and the brown-rot fungus Gloeophyllum trabeum (GtLPMO9A-2) [27]. Compared to these enzymes, Pa LPMO9H seems to behave differently.…”

Section: Resultsmentioning

confidence: 99%

The Podospora anserina lytic polysaccharide monooxygenase PaLPMO9H catalyzes oxidative cleavage of diverse plant cell wall matrix glycans

Fanuel

Garajová

Ropartz

et al. 2017

Biotechnol Biofuels

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BackgroundThe enzymatic conversion of plant biomass has been recently revolutionized by the discovery of lytic polysaccharide monooxygenases (LPMO) that catalyze oxidative cleavage of polysaccharides. These powerful enzymes are secreted by a large number of fungal saprotrophs and are important components of commercial enzyme cocktails used for industrial biomass conversion. Among the 33 AA9 LPMOs encoded by the genome of Podospora anserina, the PaLPMO9H enzyme catalyzes mixed C1/C4 oxidative cleavage of cellulose and cello-oligosaccharides. Activity of PaLPMO9H on several hemicelluloses has been suggested, but the regioselectivity of the cleavage remained to be determined.ResultsIn this study, we investigated the activity of PaLPMO9H on mixed-linkage glucans, xyloglucan and glucomannan using tandem mass spectrometry and ion mobility–mass spectrometry. Structural analysis of the released products revealed that PaLPMO9H catalyzes C4 oxidative cleavage of mixed-linkage glucans and mixed C1/C4 oxidative cleavage of glucomannan and xyloglucan. Gem-diols and ketones were produced at the non-reducing end, while aldonic acids were produced at the reducing extremity of the products.ConclusionThe ability of PaLPMO9H to target polysaccharides, differing from cellulose by their linkages, glycosidic composition and/or presence of sidechains, could be advantageous for this coprophilous fungus when catabolizing highly variable polysaccharides and for the development of optimized enzyme cocktails in biorefineries.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0749-5) contains supplementary material, which is available to authorized users.

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FgLPMO9A from Fusarium graminearum cleaves xyloglucan independently of the backbone substitution pattern

Cited by 48 publications

References 44 publications

Methylation of the N‐terminal histidine protects a lytic polysaccharide monooxygenase from auto‐oxidative inactivation

Methylation of the N‐terminal histidine protects a lytic polysaccharide monooxygenase from auto‐oxidative inactivation

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

The Podospora anserina lytic polysaccharide monooxygenase PaLPMO9H catalyzes oxidative cleavage of diverse plant cell wall matrix glycans

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