scholarly journals Pseudomonas cellulose-binding domains mediate their effects by increasing enzyme substrate proximity

1998 ◽  
Vol 331 (3) ◽  
pp. 775-781 ◽  
Author(s):  
David N. BOLAM ◽  
Antonio CIRUELA ◽  
Simon McQUEEN-MASON ◽  
Peter SIMPSON ◽  
Michael P. WILLIAMSON ◽  
...  
Keyword(s):  
Plant Cell ◽  
Mode Of Action ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Cellulase Activity ◽  
Type Ii ◽  
Binding Domains ◽  
Enzyme Substrate ◽  
Tryptophan Residues ◽  
Cellulose Binding

To investigate the mode of action of cellulose-binding domains (CBDs), the Type II CBD from Pseudomonas fluorescenssubsp. cellulosaxylanase A (XYLACBD) and cellulase E (CELECBD) were expressed as individual entities or fused to the catalytic domain of a Clostridium thermocellumendoglucanase (EGE). The two CBDs exhibited similar Ka values for bacterial microcrystalline cellulose (CELECBD, 1.62×106 M-1; XYLACBD, 1.83×106 M-1) and acid-swollen cellulose (CELECBD, 1.66×106 M-1; XYLACBD, 1.73×106 M-1). NMR spectra of XYLACBD titrated with cello-oligosaccharides showed that the environment of three tryptophan residues was affected when the CBD bound cellohexaose, cellopentaose or cellotetraose. The Ka values of the XYLACBD for C6, C5 and C4 cello-oligosaccharides were estimated to be 3.3×102, 1.4×102 and 4.0×101 M-1 respectively, suggesting that the CBD can accommodate at least six glucose molecules and has a much higher affinity for insoluble cellulose than soluble oligosaccharides. Fusion of either the CELECBD or XYLACBD to the catalytic domain of EGE potentiated the activity of the enzyme against insoluble forms of cellulose but not against carboxymethylcellulose. The increase in cellulase activity was not observed when the CBDs were incubated with the catalytic domain of either EGE or XYLA, with insoluble cellulose and a cellulose/hemicellulose complex respectively as the substrates. PseudomonasCBDs did not induce the extension of isolated plant cell walls nor weaken cellulose paper strips in the same way as a class of plant cell wall proteins called expansins. The XYLACBD and CELECBD did not release small particles from the surface of cotton. The significance of these results in relation to the mode of action of Type II CBDs is discussed.

scholarly journals The type II and X cellulose-binding domains of Pseudomonas xylanase A potentiate catalytic activity against complex substrates by a common mechanism

1999 ◽  
Vol 342 (2) ◽  
pp. 473-480 ◽  
Author(s):  
Jaitinder GILL ◽  
Jane E. RIXON ◽  
David N. BOLAM ◽  
Simon MCQUEEN-MASON ◽  
Peter J. SIMPSON ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Wall Material ◽  
Common Mechanism ◽  
Type Ii ◽  
Binding Domains ◽  
Covalently Linked ◽  
Cellulose Binding ◽  
Internal Domain

Xylanase A (Pf Xyn10A), in common with several other Pseudomonas fluorescens subsp. cellulosa polysaccharidases, consists of a Type II cellulose-binding domain (CBD), a catalytic domain (Pf Xyn10ACD) and an internal domain that exhibits homology to Type X CBDs. The Type X CBD of Pf Xyn10A, expressed as a discrete entity (CBDX) or fused to the catalytic domain (Pf Xyn10A′), bound to amorphous and bacterial microcrystalline cellulose with a Ka of 2.5×105 M-1. CBDX exhibited no affinity for soluble forms of cellulose or cello-oligosaccharides, suggesting that the domain interacts with multiple cellulose chains in the insoluble forms of the polysaccharide. Pf Xyn10A′ was 2-3 times more active against cellulose-hemicellulose complexes than Pf Xyn10ACD; however, Pf Xyn10A′ and Pf Xyn10ACD exhibited the same activity against soluble substrates. CBDX did not disrupt the structure of plant-cell-wall material or bacterial microcrystalline cellulose, and did not potentiate Pf Xyn10ACD when not covalently linked to the enzyme. There was no substantial difference in the affinity of full-length Pf Xyn10A and the enzyme's Type II CBD for cellulose. The activity of Pf Xyn10A against cellulose-hemicellulose complexes was similar to that of Pf Xyn10A′, and a derivative of Pf Xyn10A in which the Type II CBD is linked to the Pf Xyn10ACD via a serine-rich linker sequence [Bolam, Cireula, McQueen-Mason, Simpson, Williamson, Rixon, Boraston, Hazlewood and Gilbert (1998) Biochem J. 331, 775-781]. These data indicate that CBDX is functional in Pf Xyn10A and that no synergy, either in ligand binding or in the potentiation of catalysis, is evident between the Type II and X CBDs of the xylanase.

scholarly journals Evidence that linker sequences and cellulose-binding domains enhance the activity of hemicellulases against complex substrates

1996 ◽  
Vol 319 (2) ◽  
pp. 515-520 ◽  
Author(s):  
Gary W BLACK ◽  
Jane E RIXON ◽  
Jonathan H. CLARKE ◽  
Geoffrey P. HAZLEWOOD ◽  
Michael K. THEODOROU ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Full Length ◽  
Wall Material ◽  
Catalytic Domains ◽  
Binding Domains ◽  
Cellulose Binding ◽  
Derivatives Of

Xylanase A (XYLA) and arabinofuranosidase C (XYLC) from Pseudomonas fluorescens subsp. cellulosa are modular enzymes consisting of discrete cellulose-binding domains (CBDs) and catalytic domains joined by serine-rich linker sequences. To evaluate the role of the CBDs and interdomain regions, the capacity of full-length and truncated derivatives of the two enzymes, lacking either the linker sequences or CBDs, to hydrolyse a range of substrates, and bind to cellulose, was determined. Removal of the CBDs did not affect either the activity of XYLA or XYLC against soluble arabinoxylan. Similarly, deletion of the linker sequences did not alter the affinity of the enzymes for cellulose or their activity against soluble substrates, even when bound to cellulose via the CBDs. Truncated derivatives of XYLA lacking either the linker sequences or the CBD were less active against xylan contained in cellulose-hemicellulose complexes, compared with the full-length xylanase. Similarly, removal of the CBD from XYLC diminished the activity of the enzyme (XYLC´´´) against plant-cell-wall material containing highly substituted arabinoxylan. The role of CBDs and linker sequences in the catalytic activity of hemicellulases against the plant cell wall is discussed.

scholarly journals Homologous xylanases from Clostridium thermocellum: evidence for bi-functional activity, synergism between xylanase catalytic modules and the presence of xylan-binding domains in enzyme complexes

1999 ◽  
Vol 342 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Ana C. FERNANDES ◽  
Carlos M. G. A. FONTES ◽  
Harry J. GILBERT ◽  
Geoffrey P. HAZLEWOOD ◽  
Tito H. FERNANDES ◽  
...  
Keyword(s):  
Clostridium Thermocellum ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Glycosyl Hydrolase ◽  
Biochemical Properties ◽  
Binding Domain ◽  
Binding Domains ◽  
A Cell ◽  
Cellulose Binding ◽  
Hydrolysis Of

Clostridium thermocellum produces a consortium of plant-cell-wall hydrolases that form a cell-bound multi-enzyme complex called the cellulosome. In the present study two similar xylanase genes, xynU and xynV, were cloned from C. thermocellum strain YS and sequenced. The deduced primary structures of both xylanases, xylanase U (XylU) and xylanase V (XylV), were homologous with the previously characterized xylanases from C. thermocellum strain F1. Truncated derivatives of XylV were produced and their biochemical properties were characterized. The xylanases were shown to be remarkably thermostable and resistant to proteolytic inactivation. The catalytic domains hydrolysed xylan by a typical endo-mode of action. The type VI cellulose-binding domain (CBD) homologue of XylV bound xylan and, to a smaller extent, Avicel and acid-swollen cellulose. Deletion of the CBD from XylV abolished the capacity of the enzymes to bind polysaccharides. The polysaccharide-binding domain was shown to have a key role in the hydrolysis of insoluble substrates by XylV. The C-terminal domain of XylV, which is absent from XylU, removed acetyl groups from acetylated xylan and acted in synergy with the glycosyl hydrolase catalytic domain of the enzyme to elicit the hydrolysis of acetylated xylan.

scholarly journals Synergistic Effect of Different Plant Cell Wall–Degrading Enzymes Is Important for Virulence of Fusarium graminearum

2017 ◽  
Vol 30 (11) ◽  
pp. 886-895 ◽  
Author(s):  
Maria Chiara Paccanaro ◽  
Luca Sella ◽  
Carla Castiglioni ◽  
Francesca Giacomello ◽  
Ana Lilia Martínez-Rocha ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fusarium Graminearum ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Xylanase Activity ◽  
Cellulase Activity ◽  
Wild Type ◽  
Cell Wall Degrading Enzymes ◽  
Xylanase Production ◽  
Significant Difference

Endo-polygalacturonases (PGs) and xylanases have been shown to play an important role during pathogenesis of some fungal pathogens of dicot plants, while their role in monocot pathogens is less defined. Pg1 and xyr1 genes of the wheat pathogen Fusarium graminearum encode the main PG and the major regulator of xylanase production, respectively. Single- and double-disrupted mutants for these genes were obtained to assess their contribution to fungal infection. Compared with wild-type strain, the ∆pg mutant showed a nearly abolished PG activity, slight reduced virulence on soybean seedlings, but no significant difference in disease symptoms on wheat spikes; the ∆xyr mutant was strongly reduced in xylanase activity and moderately reduced in cellulase activity but was as virulent as wild type on both soybean and wheat plants. Consequently, the ΔpgΔxyr double mutant was impaired in xylanase, PG, and cellulase activities but, differently from single mutants, was significantly reduced in virulence on both plants. These findings demonstrate that the concurrent presence of PG, xylanase, and cellulase activities is necessary for full virulence. The observation that the uronides released from wheat cell wall after a F. graminearum PG treatment were largely increased by the fungal xylanases suggests that these enzymes act synergistically in deconstructing the plant cell wall.

scholarly journals Arabinanase A from Pseudomonas fluorescens subsp. cellulosa exhibits both an endo- and an exo- mode of action

1997 ◽  
Vol 323 (2) ◽  
pp. 547-555 ◽  
Author(s):  
Vincent A. McKIE ◽  
Gary W. BLACK ◽  
Sarah J. MILLWARD-SADLER ◽  
Geoffrey P. HAZLEWOOD ◽  
Judith I. LAURIE ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Mode Of Action ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Genomic Library ◽  
Glycosyl Hydrolase ◽  
Single Copy ◽  
Terminal Sequence ◽  
Reading Frame ◽  
Significant Release

Pseudomonas fluorescens subsp. cellulosa expressed arabinanase activity when grown on media supplemented with arabinan or arabinose. Arabinanase activity was not induced by the inclusion of other plant structural polysaccharides, and was repressed by the addition of glucose. The majority of the Pseudomonas arabinanase activity was extracellular. Screening of a genomic library of P. fluorescens subsp. cellulosa DNA constructed in Lambda ZAPII, for recombinants that hydrolysed Red-dyed arabinan, identified five arabinan-degrading plaques. Each of the phage contained the same Pseudomonas arabinanase gene, designated arbA, which was present as a single copy in the Pseudomonas genome. The nucleotide sequence of arbA revealed an open reading frame of 1041 bp encoding a protein, designated arabinanase A (ArbA), of Mr 39438. The N-terminal sequence of ArbA exhibited features typical of a prokaryotic signal peptide. Analysis of the primary structure of ArbA indicated that, unlike most Pseudomonas plant cell wall hydrolases, it did not contain linker sequences or have a modular structure, but consisted of a single catalytic domain. Sequence comparison between the Pseudomonas arabinanase and proteins in the SWISS-PROT database showed that ArbA exhibits greatest sequence identity with arabinanase A from Aspergillus niger, placing the enzyme in glycosyl hydrolase Family 43. The significance of the differing substrate specificities of enzymes in Family 43 is discussed. ArbA purifed from a recombinant strain of Escherichia coli had an Mr of 34000 and an N-terminal sequence identical to residues 32–51 of the deduced sequence of ArbA, and hydrolysed linear arabinan, carboxymethylarabinan and arabino-oligosaccharides. The enzyme displayed no activity against other plant structural polysaccharides, including branched sugar beet arabinan. ArbA produced almost exclusively arabinotriose from linear arabinan and appeared to hydrolyse arabino-oligosaccharides by successively releasing arabinotriose. ArbA and the Aspergillus arabinanase mediated a decrease in the viscosity of linear arabinan that was associated with a significant release of reducing sugar. We propose that ArbA is an arabinanase that exhibits both an endo- and an exo- mode of action.

scholarly journals Characterization of hybrid proteins consisting of the catalytic domains of Clostridium and Ruminococcus endoglucanases, fused to Pseudomonas non-catalytic cellulose-binding domains

1991 ◽  
Vol 279 (3) ◽  
pp. 787-792 ◽  
Author(s):  
D M Poole ◽  
A J Durrant ◽  
G P Hazlewood ◽  
H J Gilbert
Keyword(s):  
Catalytic Domain ◽  
Binding Capacity ◽  
Binding Domains ◽  
Hybrid Proteins ◽  
C Terminus ◽  
N Terminus ◽  
Fusion Enzymes ◽  
Cellulose Binding

The N-terminal 160 or 267 residues of xylanase A from Pseudomonas fluorescens subsp. cellulosa, containing a non-catalytic cellulose-binding domain (CBD), were fused to the N-terminus of the catalytic domain of endoglucanase E (EGE') from Clostridium thermocellum. A further hybrid enzyme was constructed consisting of the 347 N-terminal residues of xylanase C (XYLC) from P. fluorescens subsp. cellulosa, which also constitutes a CBD, fused to the N-terminus of endoglucanase A (EGA) from Ruminococcus albus. The three hybrid enzymes bound to insoluble cellulose, and could be eluted such that cellulose-binding capacity and catalytic activity were retained. The catalytic properties of the fusion enzymes were similar to EGE' and EGA respectively. Residues 37-347 and 34-347 of XYLC were fused to the C-terminus of EGE' and the 10 amino acids encoded by the multiple cloning sequence of pMTL22p respectively. The two hybrid proteins did not bind cellulose, although residues 39-139 of XYLC were shown previously to constitute a functional CBD. The putative role of the P. fluorescens subsp. cellulosa CBD in cellulase action is discussed.

scholarly journals X-Ray Crystal Structure of the Multidomain Endoglucanase Cel9G from Clostridium cellulolyticum Complexed with Natural and Synthetic Cello-Oligosaccharides

2003 ◽  
Vol 185 (14) ◽  
pp. 4127-4135 ◽  
Author(s):  
David Mandelman ◽  
Anne Belaich ◽  
J. P. Belaich ◽  
Nushin Aghajari ◽  
Hugues Driguez ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Catalytic Domain ◽  
Cellulose Degradation ◽  
Cellulase Activity ◽  
Structural Basis ◽  
Crystalline Cellulose ◽  
X Ray ◽  
Clostridium Cellulolyticum ◽  
Active Site Cleft ◽  
Cellulose Binding

ABSTRACT Complete cellulose degradation is the first step in the use of biomass as a source of renewable energy. To this end, the engineering of novel cellulase activity, the activity responsible for the hydrolysis of the β-1,4-glycosidic bonds in cellulose, is a topic of great interest. The high-resolution X-ray crystal structure of a multidomain endoglucanase from Clostridium cellulolyticum has been determined at a 1.6-Å resolution. The endoglucanase, Cel9G, is comprised of a family 9 catalytic domain attached to a family IIIc cellulose-binding domain. The two domains together form a flat platform onto which crystalline cellulose is suggested to bind and be fed into the active-site cleft for endolytic hydrolysis. To further dissect the structural basis of cellulose binding and hydrolysis, the structures of Cel9G in the presence of cellobiose, cellotriose, and a DP-10 thio-oligosaccharide inhibitor were resolved at resolutions of 1.7, 1.8, and 1.9 Å, respectively.

scholarly journals Functional Analysis of the Carbohydrate-Binding Domains of Erwinia chrysanthemi Cel5 (Endoglucanase Z) and an Escherichia coli Putative Chitinase

1999 ◽  
Vol 181 (15) ◽  
pp. 4611-4616 ◽  
Author(s):  
Helen D. Simpson ◽  
Frederic Barras
Keyword(s):  
Escherichia Coli ◽  
Catalytic Domain ◽  
Three Dimensional ◽  
Site Directed Mutagenesis ◽  
Erwinia Chrysanthemi ◽  
Dimensional Structure ◽  
Carbohydrate Binding ◽  
Binding Domains ◽  
Cellulose Binding

ABSTRACT The Cel5 cellulase (formerly known as endoglucanase Z) fromErwinia chrysanthemi is a multidomain enzyme consisting of a catalytic domain, a linker region, and a cellulose binding domain (CBD). A three-dimensional structure of the CBDCel5 has previously been obtained by nuclear magnetic resonance. In order to define the role of individual residues in cellulose binding, site-directed mutagenesis was performed. The role of three aromatic residues (Trp18, Trp43, and Tyr44) in cellulose binding was demonstrated. The exposed potential hydrogen bond donors, residues Gln22 and Glu27, appeared not to play a role in cellulose binding, whereas residue Asp17 was found to be important for the stability of Cel5. A deletion mutant lacking the residues Asp17 to Pro23 bound only weakly to cellulose. The sequence of CBDCel5 exhibits homology to a series of five repeating domains of a putative large protein, referred to as Yheb, from Escherichia coli. One of the repeating domains (Yheb1), consisting of 67 amino acids, was cloned from the E. coli chromosome and purified by metal chelating chromatography. While CBDCel5 bound to both cellulose and chitin, Yheb1 bound well to chitin, but only very poorly to cellulose. The Yheb protein contains a region that exhibits sequence homology with the catalytic domain of a chitinase, which is consistent with the hypothesis that the Yheb protein is a chitinase.

scholarly journals Crystallization and preliminary crystallographic studies of a novel noncatalytic carbohydrate-binding module from theRuminococcus flavefacienscellulosome

2015 ◽  
Vol 71 (1) ◽  
pp. 45-48 ◽  
Author(s):  
Immacolata Venditto ◽  
Arun Goyal ◽  
Andrew Thompson ◽  
Luis M. A. Ferreira ◽  
Carlos M. G. A. Fontes ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Catalytic Domain ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Binding ◽  
Cellulolytic Bacterium ◽  
Modular Architecture ◽  
Carbohydrate Binding Modules ◽  
Fundamental Biological Process

Microbial degradation of the plant cell wall is a fundamental biological process with considerable industrial importance. Hydrolysis of recalcitrant polysaccharides is orchestrated by a large repertoire of carbohydrate-active enzymes that display a modular architecture in which a catalytic domain is connectedvialinker sequences to one or more noncatalytic carbohydrate-binding modules (CBMs). CBMs direct the appended catalytic modules to their target substrates, thus potentiating catalysis. The genome of the most abundant ruminal cellulolytic bacterium,Ruminococcus flavefaciensstrain FD-1, provides an opportunity to discover novel cellulosomal proteins involved in plant cell-wall deconstruction. It encodes a modular protein comprising a glycoside hydrolase family 9 catalytic module (GH9) linked to two unclassified tandemly repeated CBMs (termed CBM-Rf6A and CBM-Rf6B) and a C-terminal dockerin. The novel CBM-Rf6A from this protein has been crystallized and data were processed for the native and a selenomethionine derivative to 1.75 and 1.5 Å resolution, respectively. The crystals belonged to orthorhombic and cubic space groups, respectively. The structure was solved by a single-wavelength anomalous dispersion experiment using theCCP4 program suite andSHELXC/D/E.

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