scholarly journals Functional Analyses of Multiple Lichenin-Degrading Enzymes from the Rumen Bacterium Ruminococcus albus 8

2011 ◽  
Vol 77 (21) ◽  
pp. 7541-7550 ◽  
Author(s):  
Michael Iakiviak ◽  
Roderick I. Mackie ◽  
Isaac K. O. Cann
Keyword(s):  
Plant Cell Wall ◽  
Bioinformatic Analysis ◽  
Major Product ◽  
Glycoside Hydrolases ◽  
Rumen Bacterium ◽  
Cell Wall Polysaccharides ◽  
Ruminococcus Albus ◽  
Content Type ◽  
Wide Range ◽  
Functional Analyses

ABSTRACTRuminococcus albus8 is a fibrolytic ruminal bacterium capable of utilization of various plant cell wall polysaccharides. A bioinformatic analysis of a partial genome sequence ofR. albusrevealed several putative enzymes likely to hydrolyze glucans, including lichenin, a mixed-linkage polysaccharide of glucose linked together in β-1,3 and β-1,4 glycosidic bonds. In the present study, we demonstrate the capacity of four glycoside hydrolases (GHs), derived fromR. albus, to hydrolyze lichenin. Two of the genes encoded GH family 5 enzymes (Ra0453 and Ra2830), one gene encoded a GH family 16 enzyme (Ra0505), and the last gene encoded a GH family 3 enzyme (Ra1595). Each gene was expressed inEscherichia coli, and the recombinant protein was purified to near homogeneity. Upon screening on a wide range of substrates, Ra0453, Ra2830, and Ra0505 displayed different hydrolytic properties, as they released unique product profiles. The Ra1595 protein, predicted to function as a β-glucosidase, preferred cleavage of a nonreducing end glucose when linked by a β-1,3 glycosidic bond to the next glucose residue. The major product of Ra0505 hydrolysis of lichenin was predicted to be a glucotriose that was degraded only by Ra0453 to glucose and cellobiose. Most importantly, the four enzymes functioned synergistically to hydrolyze lichenin to glucose, cellobiose, and cellotriose. This lichenin-degrading enzyme mix should be of utility as an additive to feeds administered to monogastric animals, especially those high in fiber.

scholarly journals Purification, crystallization and preliminary crystallographic analysis of Gan1D, a GH1 6-phospho-β-galactosidase fromGeobacillus stearothermophilusT1

2014 ◽  
Vol 70 (2) ◽  
pp. 225-231 ◽  
Author(s):  
Shifra Lansky ◽  
Arie Zehavi ◽  
Roie Dann ◽  
Hay Dvir ◽  
Hassan Belrhali ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Extracellular Enzymes ◽  
Biochemical Characterization ◽  
Crystal Structure Analysis ◽  
Crystallographic Analysis ◽  
Glycoside Hydrolases ◽  
Cell Wall Polysaccharides ◽  
Data Set ◽  
Cell Parameters ◽  
Wide Range

Geobacillus stearothermophilusT1 is a Gram-positive thermophilic soil bacterium that contains an extensive system for the utilization of plant cell-wall polysaccharides, including xylan, arabinan and galactan. The bacterium uses a number of extracellular enzymes that break down the high-molecular-weight polysaccharides into short oligosaccharides, which enter the cell and are further hydrolyzed into sugar monomers by dedicated intracellular glycoside hydrolases. The interest in the biochemical characterization and structural analysis of these proteins originates mainly from the wide range of their potential biotechnological applications. Studying the different hemicellulolytic utilization systems inG. stearothermophilusT1, a new galactan-utilization gene cluster was recently identified, which encodes a number of proteins, one of which is a GH1 putative 6-phospho-β-galactosidase (Gan1D). Gan1D has recently been cloned, overexpressed, purified and crystallized as part of its comprehensive structure–function study. The best crystals obtained for this enzyme belonged to the triclinic space groupP1, with average crystallographic unit-cell parameters ofa = 67.0,b= 78.1,c= 92.1 Å, α = 102.4, β = 93.5, γ = 91.7°. A full diffraction data set to 1.33 Å resolution has been collected for the wild-type enzyme, as measured from flash-cooled crystals at 100 K, using synchrotron radiation. These data are currently being used for the detailed three-dimensional crystal structure analysis of Gan1D.

scholarly journals Biochemical Analyses of Multiple Endoxylanases from the Rumen Bacterium Ruminococcus albus 8 and Their Synergistic Activities with Accessory Hemicellulose-Degrading Enzymes

2011 ◽  
Vol 77 (15) ◽  
pp. 5157-5169 ◽  
Author(s):  
Young Hwan Moon ◽  
Michael Iakiviak ◽  
Stefan Bauer ◽  
Roderick I. Mackie ◽  
Isaac K. O. Cann
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Biofuel Production ◽  
Rumen Bacterium ◽  
Ruminococcus Albus ◽  
Content Type ◽  
Chemical Complexity ◽  
Degrading Enzymes ◽  
Modular Architectures

ABSTRACTRuminococcus albus8 is a ruminal bacterium capable of metabolizing hemicellulose and cellulose, the major components of the plant cell wall. The enzymes that allow this bacterium to capture energy from the two polysaccharides, therefore, have potential application in plant cell wall depolymerization, a process critical to biofuel production. For this purpose, a partial genome sequence ofR. albus8 was generated. The genomic data depicted a bacterium endowed with multiple forms of plant cell wall-degrading enzymes. The endoxylanases ofR. albus8 exhibited diverse modular architectures, including incorporation of a catalytic module, a carbohydrate binding module, and a carbohydrate esterase module in a single polypeptide. The accessory enzymes of xylan degradation were a β-xylosidase, an α-l-arabinofuranosidase, and an α-glucuronidase. We hypothesized that due to the chemical complexity of the hemicellulose encountered in the rumen, the bacterium uses multiple endoxylanases, with subtle differences in substrate specificities, to attack the substrate, while the accessory enzymes hydrolyze the products to simple sugars for metabolism. To test this hypothesis, the genes encoding the predicted endoxylanases were expressed, and the proteins were biochemically characterized either alone or in combination with accessory enzymes. The different endoxylanase families exhibited different patterns of product release, with the family 11 endoxylanases releasing more products in synergy with the accessory enzymes from the more complex substrates. Aside from the insights into hemicellulose degradation byR. albus8, this report should enhance our knowledge on designing effective enzyme cocktails for release of fermentable sugars in the biofuel industry.

scholarly journals Metatranscriptomic Analyses of Plant Cell Wall Polysaccharide Degradation by Microorganisms in the Cow Rumen

2014 ◽  
Vol 81 (4) ◽  
pp. 1375-1386 ◽  
Author(s):  
Xin Dai ◽  
Yan Tian ◽  
Jinting Li ◽  
Xiaoyun Su ◽  
Xuewei Wang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Average Length ◽  
Glycoside Hydrolases ◽  
Carbohydrate Binding ◽  
Cell Wall Polysaccharide ◽  
Cell Wall Polysaccharides ◽  
Content Type ◽  
Carbohydrate Binding Modules

ABSTRACTThe bovine rumen represents a highly specialized bioreactor where plant cell wall polysaccharides (PCWPs) are efficiently deconstructed via numerous enzymes produced by resident microorganisms. Although a large number of fibrolytic genes from rumen microorganisms have been identified, it remains unclear how they are expressed in a coordinated manner to efficiently degrade PCWPs. In this study, we performed a metatranscriptomic analysis of the rumen microbiomes of adult Holstein cows fed a fiber diet and obtained a total of 1,107,083 high-quality non-rRNA reads with an average length of 483 nucleotides. Transcripts encoding glycoside hydrolases (GHs) and carbohydrate binding modules (CBMs) accounted for ∼1% and ∼0.1% of the total non-rRNAs, respectively. The majority (∼98%) of the putative cellulases belonged to four GH families (i.e., GH5, GH9, GH45, and GH48) and were primarily synthesized byRuminococcusandFibrobacter. Notably, transcripts for GH48 cellobiohydrolases were relatively abundant compared to the abundance of transcripts for other cellulases. Two-thirds of the putative hemicellulases were of the GH10, GH11, and GH26 types and were produced by members of the generaRuminococcus,Prevotella, andFibrobacter. Most (∼82%) predicted oligosaccharide-degrading enzymes were GH1, GH2, GH3, and GH43 proteins and were from a diverse group of microorganisms. Transcripts for CBM10 and dockerin, key components of the cellulosome, were also relatively abundant. Our results provide metatranscriptomic evidence in support of the notion that members of the generaRuminococcus,Fibrobacter, andPrevotellaare predominant PCWP degraders and point to the significant contribution of GH48 cellobiohydrolases and cellulosome-like structures to efficient PCWP degradation in the cow rumen.

scholarly journals L-Rhamnose Metabolism inClostridium beijerinckiiStrain DSM 6423

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Mamou Diallo ◽  
Andre D. Simons ◽  
Hetty van der Wal ◽  
Florent Collas ◽  
Bwee Houweling-Tan ◽  
...  
Keyword(s):  
First Generation ◽  
Major Product ◽  
Green Macroalgae ◽  
Content Type ◽  
Sugar Fermentation ◽  
Bacterial Microcompartment ◽  
General Metabolism ◽  
Wide Range ◽  
Biomass Resources ◽  
Fuels And Chemicals

ABSTRACTMacroalgae (or seaweeds) are considered potential biomass feedstocks for the production of renewable fuels and chemicals. Their sugar composition is different from that of lignocellulosic biomasses, and in green species, includingUlva lactuca, the major sugars arel-rhamnose andd-glucose.C. beijerinckiiDSM 6423 utilized these sugars in aU. lactucahydrolysate to produce acetic acid, butyric acid, isopropanol, butanol, and ethanol (IBE), and 1,2-propanediol.d-Glucose was almost completely consumed in diluted hydrolysates, whilel-rhamnose ord-xylose was only partially utilized. In this study, the metabolism ofl-rhamnose byC. beijerinckiiDSM 6423 was investigated to improve its utilization from natural resources. Fermentations ond-glucose,l-rhamnose, and a mixture ofd-glucose andl-rhamnose were performed. Onl-rhamnose, the cultures showed low growth and sugar consumption and produced 1,2-propanediol, propionic acid, andn-propanol in addition to acetic and butyric acids, whereas ond-glucose, IBE was the major product. On ad-glucose–l-rhamnose mixture, both sugars were converted simultaneously andl-rhamnose consumption was higher, leading to high levels of 1,2-propanediol (78.4 mM), in addition to 59.4 mM butanol and 31.9 mM isopropanol. Genome and transcriptomics analysis ofd-glucose- andl-rhamnose-grown cells revealed the presence and transcription of genes involved inl-rhamnose utilization and in bacterial microcompartment (BMC) formation. These data provide useful insights into the metabolic pathways involved inl-rhamnose utilization and the effects on the general metabolism (glycolysis, early sporulation, and stress response) induced by growth onl-rhamnose.IMPORTANCEA prerequisite for a successful biobased economy is the efficient conversion of biomass resources into useful products, such as biofuels and bulk and specialty chemicals. In contrast to other industrial microorganisms, natural solvent-producing clostridia utilize a wide range of sugars, including C5, C6, and deoxy-sugars, for production of long-chain alcohols (butanol and 2,3-butanediol), isopropanol, acetone,n-propanol, and organic acids. Butanol production by clostridia from first-generation sugars is already a commercial process, but for the expansion and diversification of the acetone, butanol, and ethanol (ABE)/IBE process to other substrates, more knowledge is needed on the regulation and physiology of fermentation of sugar mixtures. Green macroalgae, produced in aquaculture systems, harvested from the sea or from tides, can be processed into hydrolysates containing mixtures ofd-glucose andl-rhamnose, which can be fermented. The knowledge generated in this study will contribute to the development of more efficient processes for macroalga fermentation and of mixed-sugar fermentation in general.

scholarly journals Glycoside Hydrolase Genes Are Required for Virulence ofAgrobacterium tumefaciensonBryophyllum daigremontianaand Tomato

2019 ◽  
Vol 85 (15) ◽  
Author(s):  
Stephanie L. Mathews ◽  
Haylea Hannah ◽  
Hillary Samagaio ◽  
Camille Martin ◽  
Eleanor Rodriguez-Rassi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Plant Cell ◽  
Crown Gall ◽  
Plant Cell Wall ◽  
Tumor Formation ◽  
Glycoside Hydrolases ◽  
Plant Host ◽  
Content Type ◽  
Limited Digestion

ABSTRACTAgrobacterium tumefaciensis a rhizosphere bacterium that can infect wound sites on plants. The bacterium transfers a segment of DNA (T-DNA) from the Ti plasmid to the plant host cell via a type IV secretion system where the DNA becomes integrated into the host cell chromosomes. The expression of T-DNA in the plant results in tumor formation. Although the binding of the bacteria to plant surfaces has been studied previously, there is little work on possible interactions of the bacteria with the plant cell wall. Seven of the 48 genes encoding putative glycoside hydrolases (Atu2295,Atu2371,Atu3104,Atu3129,Atu4560,Atu4561, andAtu4665) in the genome ofA. tumefaciensC58 were found to play a role in virulence on tomato andBryophyllum daigremontiana. Two of these genes (pglAandpglB;Atu3129andAtu4560) encode enzymes capable of digesting polygalacturonic acid and, thus, may play a role in the digestion of pectin. One gene (arfA;Atu3104) encodes an arabinosylfuranosidase, which could remove arabinose from the ends of polysaccharide chains. Two genes (bglAandbglB;Atu2295andAtu4561) encode proteins with β-glycosidase activity and could digest a variety of plant cell wall oligosaccharides and polysaccharides. One gene (xynA;Atu2371) encodes a putative xylanase, which may play a role in the digestion of xylan. Another gene (melA;Atu4665) encodes a protein with α-galactosidase activity and may be involved in the breakdown of arabinogalactans. Limited digestion of the plant cell wall byA. tumefaciensmay be involved in tumor formation on tomato andB. daigremontiana.IMPORTANCEA. tumefaciensis used in the construction of genetically engineered plants, as it is able to transfer DNA to plant hosts. Knowledge of the mechanisms of DNA transfer and the genes required will aid in the understanding of this process. Manipulation of glycoside hydrolases may increase transformation and widen the host range of the bacterium.A. tumefaciensalso causes disease (crown gall tumors) on a variety of plants, including stone fruit trees, grapes, and grafted ornamentals such as roses. It is possible that compounds that inhibit glycoside hydrolases could be used to control crown gall disease caused byA. tumefaciens.

scholarly journals Revisiting the Regulation of the Primary Scaffoldin Gene in Clostridium thermocellum

2017 ◽  
Vol 83 (8) ◽  
Author(s):  
Lizett Ortiz de Ora ◽  
Iván Muñoz-Gutiérrez ◽  
Edward A. Bayer ◽  
Yuval Shoham ◽  
Raphael Lamed ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Consolidated Bioprocessing ◽  
Present Report ◽  
Genetic Regulation ◽  
Regulatory Mechanisms ◽  
Start Codon ◽  
Protein Subunit ◽  
Cell Wall Polysaccharides ◽  
Stem Loop ◽  
Content Type

ABSTRACT Cellulosomes are considered to be one of the most efficient systems for the degradation of plant cell wall polysaccharides. The central cellulosome component comprises a large, noncatalytic protein subunit called scaffoldin. Multiple saccharolytic enzymes are incorporated into the scaffoldins via specific high-affinity cohesin-dockerin interactions. Recently, the regulation of genes encoding certain cellulosomal components by multiple RNA polymerase alternative σI factors has been demonstrated in Clostridium (Ruminiclostridium) thermocellum. In the present report, we provide experimental evidence demonstrating that the C. thermocellum cipA gene, which encodes the primary cellulosomal scaffoldin, is regulated by several alternative σI factors and by the vegetative σA factor. Furthermore, we show that previously suggested transcriptional start sites (TSSs) of C. thermocellum cipA are actually posttranscriptional processed sites. By using comparative bioinformatic analysis, we have also identified highly conserved σI- and σA-dependent promoters upstream of the primary scaffoldin-encoding genes of other clostridia, namely, Clostridium straminisolvens, Clostridium clariflavum, Acetivibrio cellulolyticus, and Clostridium sp. strain Bc-iso-3. Interestingly, a previously identified TSS of the primary scaffoldin CbpA gene of Clostridium cellulovorans matches the predicted σI-dependent promoter identified in the present work rather than the previously proposed σA promoter. With the exception of C. cellulovorans, both σI and σA promoters of primary scaffoldin genes are located more than 600 nucleotides upstream of the start codon, yielding long 5′-untranslated regions (5′-UTRs). Furthermore, these 5′-UTRs have highly conserved stem-loop structures located near the start codon. We propose that these large 5′-UTRs may be involved in the regulation of both the primary scaffoldin and other cellulosomal components. IMPORTANCE Cellulosome-producing bacteria are among the most effective cellulolytic microorganisms known. This group of bacteria has biotechnological potential for the production of second-generation biofuels and other biocommodities from cellulosic wastes. The efficiency of cellulose hydrolysis is due to their cellulosomes, which arrange enzymes in close proximity on the cellulosic substrate, thereby increasing synergism among the catalytic domains. The backbone of these multienzyme nanomachines is the scaffoldin subunit, which has been the subject of study for many years. However, its genetic regulation is poorly understood. Hence, from basic and applied points of view, it is imperative to unravel the regulatory mechanisms of the scaffoldin genes. The understanding of these regulatory mechanisms can help to improve the performance of the industrially relevant strains of C. thermocellum and related cellulosome-producing bacteria en route to the consolidated bioprocessing of biomass.

Some properties of the endo-(1 → 4)-β-D-glucanase synthesized by the anaerobic cellulolytic rumen bacterium Ruminococcus albus

1984 ◽  
Vol 30 (3) ◽  
pp. 316-321 ◽  
Author(s):  
Thomas M. Wood ◽  
Catriona A. Wilson
Keyword(s):  
Synthetic Medium ◽  
Culture Conditions ◽  
Polyacrylamide Gel ◽  
Rumen Bacterium ◽  
Ruminococcus Albus ◽  
Molecular Weights ◽  
Trichoderma Koningii ◽  
Large Molecular Weight ◽  
Rapid Fall ◽  
Wide Range

The extracellular and cell-bound cellulase (CM-cellulase) elaborated by the rumen bacterium Ruminococcus albus SY3 in synthetic medium was an endo-(1 → 4)-β-glucanase in that (i) it produced a rapid fall in the degree of polymerisation (1900 → 300) of H3PO4-swollen cellulose, while causing only 0.5% hydrolysis, and (ii) it released large amounts of cellotriose and smaller amounts of cellotetraose from H3PO4-swollen cellulose. The enzyme appeared in a wide range of molecular weights, which varied according to the culture conditions, but nevertheless focused at pH 6.0–6.1 in all cases in a pH gradient supported in a polyacrylamide gel. Cell-bound enzyme, which was of very large molecular weight (> 1.5 × 106), was excluded from the polyacrylamide gel. Under certain conditions, cellulose swollen in H3PO4 was hydrolysed extensively, but highly ordered cellulosic substrates were poorly hydrolysed. The enzyme acted synergistically with an endwise-acting cellobiohydrolase from the fungus Trichoderma koningii in solubilizing a microcystalline wood α-cellulose preparation (Avicel): the same cooperation was not apparent when Avicel was swollen in H3PO4 or when cellulose in the form of cotton fibre was used.

scholarly journals Cell Surface Enzyme Attachment Is Mediated by Family 37 Carbohydrate-Binding Modules, Unique to Ruminococcus albus

2008 ◽  
Vol 190 (24) ◽  
pp. 8220-8222 ◽  
Author(s):  
Anat Ezer ◽  
Erez Matalon ◽  
Sadanari Jindou ◽  
Ilya Borovok ◽  
Nof Atamna ◽  
...  
Keyword(s):  
Cell Surface ◽  
Bacterial Cell ◽  
Cellulose Degradation ◽  
Glycoside Hydrolases ◽  
Rumen Bacterium ◽  
Carbohydrate Binding ◽  
Ruminococcus Albus ◽  
System A ◽  
C Terminus ◽  
Carbohydrate Binding Modules

ABSTRACT The rumen bacterium Ruminococcus albus binds to and degrades crystalline cellulosic substrates via a unique cellulose degradation system. A unique family of carbohydrate-binding modules (CBM37), located at the C terminus of different glycoside hydrolases, appears to be responsible both for anchoring these enzymes to the bacterial cell surface and for substrate binding.

scholarly journals Role of theganSPQABOperon in Degradation of Galactan by Bacillus subtilis

2016 ◽  
Vol 198 (20) ◽  
pp. 2887-2896 ◽  
Author(s):  
Hildegard Watzlawick ◽  
Kambiz Morabbi Heravi ◽  
Josef Altenbuchner
Keyword(s):  
Bacillus Subtilis ◽  
Abc Transporter ◽  
Plant Cell Wall ◽  
Type I ◽  
Cell Wall Polysaccharides ◽  
Pectin Degradation ◽  
Content Type ◽  
Sugar Binding ◽  
Thermal Shift Assay ◽  
Thermal Shift

ABSTRACTBacillus subtilispossesses different enzymes for the utilization of plant cell wall polysaccharides. This includes a gene cluster containing galactan degradation genes (ganAandganB), two transporter component genes (ganQandganP), and the sugar-binding lipoprotein-encoding geneganS(previously known ascycB). These genes form an operon that is regulated by GanR. The degradation of galactan byB. subtilisbegins with the activity of extracellular GanB. GanB is an endo-β-1,4-galactanase and is a member of glycoside hydrolase (GH) family 53. This enzyme was active on high-molecular-weight arabinose-free galactan and mainly produced galactotetraose as well as galactotriose and galactobiose. These galacto-oligosaccharides may enter the cell via the GanQP transmembrane proteins of the galactan ABC transporter. The specificity of the galactan ABC transporter depends on the sugar-binding lipoprotein, GanS. Purified GanS was shown to bind galactotetraose and galactotriose using thermal shift assay. The energy for this transport is provided by MsmX, an ATP-binding protein. The transported galacto-oligosaccharides are further degraded by GanA. GanA is a β-galactosidase that belongs to GH family 42. The GanA enzyme was able to hydrolyze short-chain β-1,4-galacto-oligosaccharides as well as synthetic β-galactopyranosides into galactose. Thermal shift assay as well as electrophoretic mobility shift assay demonstrated that galactobiose is the inducer of the galactan operon regulated by GanR. DNase I footprinting revealed that the GanR protein binds to an operator overlapping the −35 box of the σA-type promoter of Pgan, which is located upstream ofganS.IMPORTANCEBacillus subtilisis a Gram-positive soil bacterium that utilizes different types of carbohydrates, such as pectin, as carbon sources. So far, most of the pectin degradation systems and enzymes have been thoroughly studied inB. subtilis. Nevertheless, theB. subtilisutilization system of galactan, which is found as the side chain of the rhamnogalacturonan type I complex in pectin, has remained partially studied. Here, we investigated the galactan utilization system consisting of theganSPQABoperon and its regulatorganR. This study improves our knowledge of the carbohydrate degradation systems ofB. subtilis, especially the pectin degradation systems. Moreover, the galactan-degrading enzymes may be exploited for the production of galacto-oligosaccharides, which are used as prebiotic substances in the food industry.

scholarly journals The GH10 and GH48 dual-functional catalytic domains from a multimodular glycoside hydrolase synergize in hydrolyzing both cellulose and xylan

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Yindi Chu ◽  
Zhenzhen Hao ◽  
Kaikai Wang ◽  
Tao Tu ◽  
Huoqing Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
High Efficiency ◽  
Early Stage ◽  
Glycoside Hydrolases ◽  
Cell Wall Polysaccharides ◽  
Catalytic Domains ◽  
Xylan Hydrolysis ◽  
Dual Functional

Abstract Background Regarding plant cell wall polysaccharides degradation, multimodular glycoside hydrolases (GHs) with two catalytic domains separated by one or multiple carbohydrate-binding domains are rare in nature. This special mode of domain organization endows the Caldicellulosiruptor bescii CelA (GH9-CBM3c-CBM3b-CBM3b-GH48) remarkably high efficiency in hydrolyzing cellulose. CbXyn10C/Cel48B from the same bacterium is also such an enzyme which has, however, evolved to target both xylan and cellulose. Intriguingly, the GH10 endoxylanase and GH48 cellobiohydrolase domains are both dual functional, raising the question if they can act synergistically in hydrolyzing cellulose and xylan, the two major components of plant cell wall. Results In this study, we discovered that CbXyn10C and CbCel48B, which stood for the N- and C-terminal catalytic domains, respectively, cooperatively released much more cellobiose and cellotriose from cellulose. In addition, they displayed intramolecular synergy but only at the early stage of xylan hydrolysis by generating higher amounts of xylooligosaccharides including xylotriose, xylotetraose, and xylobiose. When complex lignocellulose corn straw was used as the substrate, the synergy was found only for cellulose but not xylan hydrolysis. Conclusion This is the first report to reveal the synergy between a GH10 and a GH48 domain. The synergy discovered in this study is helpful for understanding how C. bescii captures energy from these recalcitrant plant cell wall polysaccharides. The insight also sheds light on designing robust and multi-functional enzymes for plant cell wall polysaccharides degradation.

Sign in / Sign up

Export Citation Format

Share Document