scholarly journals Carbohydrate-binding modules from a thermostable Rhodothermus marinus xylanase: cloning, expression and binding studies

1999 ◽  
Vol 345 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Maher ABOU HACHEM ◽  
Eva NORDBERG KARLSSON ◽  
Eva BARTONEK-ROXÅ ◽  
Srinivasrao RAGHOTHAMA ◽  
Peter J. SIMPSON ◽  
...  

The two N-terminally repeated carbohydrate-binding modules (CBM4-1 and CBM4-2) encoded by xyn10A from Rhodothermus marinus were produced in Escherichiacoli and purified by affinity chromatography. Binding assays to insoluble polysaccharides showed binding to insoluble xylan and to phosphoric-acid-swollen cellulose but not to Avicel or crystalline cellulose. Binding to insoluble substrates was significantly enhanced by the presence of Na+ and Ca2+ ions. The binding affinities for soluble polysaccharides were tested by affinity electrophoresis; strong binding occurred with different xylans and β-glucan. CBM4-2 displayed a somewhat higher binding affinity than CBM4-1 for both soluble and insoluble substrates but both had similar specificities. Binding to short oligosaccharides was measured by NMR; both modules bound with similar affinities. The binding of the modules was shown to be dominated by enthalpic forces. The binding modules did not contribute with any significant synergistic effects on xylan hydrolysis when incubated with a Xyn10A catalytic module. This is the first report of family 4 CBMs with affinity for both insoluble xylan and amorphous cellulose.

2000 ◽  
Vol 345 (1) ◽  
pp. 53 ◽  
Author(s):  
Maher ABOU HACHEM ◽  
Eva NORDBERG KARLSSON ◽  
Eva BARTONEK-ROXÅ ◽  
Srinivasrao RAGHOTHAMA ◽  
Peter J. SIMPSON ◽  
...  

BioResources ◽  
2007 ◽  
Vol 2 (2) ◽  
pp. 284-295
Author(s):  
Clemens Altaner ◽  
J. Paul Knox ◽  
Michael C. Jarvis

Wood cell wall polysaccharides can be probed with monoclonal antibodies and carbohydrate-binding modules (CBMs). Binding of monoclonal antibodies to β-1-4-xylan, β-1-4-mannan, β-1-3-glucan, and α-1-5-arabinan structures were observed in native Sitka spruce (Picea sitchensis (Bong.) Carrière) wood cell walls. Furthermore CBMs of different families, differing in their affinities for crystalline cellulose (3a) and amorphous cellulose (17 and 28), were shown to bind to the native wood cell walls with varying intensities. Resin channel forming cells exhibited an increased β-1-4-xylan and a decreased β-1-4-mannan content. Focusing on severe compression wood (CW) tracheids, β-1-3-glucan was found towards the cell lumen. In contrast, α-1-5-arabinan structures were present in the intercellular spaces between the round tracheids in severe CW, highlighting the importance of this polymer in cell adhesion.


2009 ◽  
Vol 66 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Svetlana Petkun ◽  
Sadanari Jindou ◽  
Linda J. W. Shimon ◽  
Sonia Rosenheck ◽  
Edward A. Bayer ◽  
...  

Family 3 carbohydrate-binding modules (CBM3s) are associated with both cellulosomal scaffoldins and family 9 glycoside hydrolases (GH9s), which are multi-modular enzymes that act on cellulosic substrates. CBM3s bind cellulose. X-ray crystal structures of these modules have established an accepted cellulose-binding mechanism based on stacking interactions between the sugar rings of cellulose and a planar array of aromatic residues located on the CBM3 surface. These planar-strip residues are generally highly conserved, although some CBM3 sequences lack one or more of these residues. In particular, CBM3b′ fromClostridium thermocellumCel9V exhibits such sequence changes and fails to bind cellulosic substrates. A crystallographic investigation of CBM3b′ has been initiated in order to understand the structural reason(s) for this inability. CBM3b′ crystallized in space groupC2221(diffraction was obtained to 2.0 Å resolution in-house) with three independent molecules in the asymmetric unit and in space groupP41212 (diffraction was obtained to 1.79 Å resolution in-house and to 1.30 Å resolution at a synchrotron) with one molecule in the asymmetric unit. The molecular structure of Cel9V CBM3b′ revealed that in addition to the loss of several cellulose-binding residues in the planar strip, changes in the backbone create a surface `hump' which could interfere with the formation of cellulose–protein surface interactions and thus prevent binding to crystalline cellulose.


2021 ◽  
Author(s):  
Yoshiki Kitano

Enzymatic hydrolysis of cellulose is a technology involved in the production of bioethanol, a potential alternative renewable energy. Many cellulases with endo- and exo- type of activity are known to hydrolyze cellulose synergistically. In this thesis, potential synergy between an endo-cellulase, Cel5B, with and without a carbohydrate- binding module (CBM6), and a new exo-cellulase, CBH1, from Trichoderma harzianum FP108 were examined during the hydrolysis of semi- crystalline cellulose (Avicel). Since CBM6 is recognized as having a high affinity for amorphous cellulose, it was hypothesized that this affinity could enhance the synergistic effect between the endo- and exo-cellulases by focusing the action to Cel5B+CBM6 on the amorphous regions of the Avicel substrate. The increased activity of Cel5B+CBM6 over Cel5B alone was confirmed. However, in contrast to our expectations, a synergistic effect was not observed between either endo- and exo-cellulase pairs. From the obtained hydrolysis yield, it was inferred that Cel5B+CBM6 may have exo-type activity that caused a competitive interaction with the exo-cellulase, which resulted in no synergy.


Author(s):  
Almog Hershko Rimon ◽  
Oded Livnah ◽  
Inna Rozman Grinberg ◽  
Lizett Ortiz de Ora ◽  
Oren Yaniv ◽  
...  

A novel member of the family 3 carbohydrate-binding modules (CBM3s) is encoded by a gene (Cthe_0271) in Clostridium thermocellum which is the most highly expressed gene in the bacterium during its growth on several types of biomass substrates. Surprisingly, CtCBM3-0271 binds to at least two different types of xylan, instead of the common binding of CBM3s to cellulosic substrates. CtCBM3-0271 was crystallized and its three-dimensional structure was solved and refined to a resolution of 1.8 Å. In order to learn more about the role of this type of CBM3, a comparative study with its orthologue from Clostridium clariflavum (encoded by the Clocl_1192 gene) was performed, and the three-dimensional structure of CcCBM3-1192 was determined to 1.6 Å resolution. Carbohydrate binding by CcCBM3-1192 was found to be similar to that by CtCBM3-0271; both exhibited binding to xylan rather than to cellulose. Comparative structural analysis of the two CBM3s provided a clear functional correlation of structure and binding, in which the two CBM3s lack the required number of binding residues in their cellulose-binding strips and thus lack cellulose-binding capabilities. This is an enigma, as CtCBM3-0271 was reported to be a highly expressed protein when the bacterium was grown on cellulose. An additional unexpected finding was that CcCBM3-1192 does not contain the calcium ion that was considered to play a structural stabilizing role in the CBM3 family. Despite the lack of calcium, the five residues that form the calcium-binding site are conserved. The absence of calcium results in conformational changes in two loops of the CcCBM3-1192 structure. In this context, superposition of the non-calcium-binding CcCBM3-1192 with CtCBM3-0271 and other calcium-binding CBM3s reveals a much broader two-loop region in the former compared with CtCBM3-0271.


Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 631 ◽  
Author(s):  
Stephen Hayes ◽  
Jennifer Mahony ◽  
Renaud Vincentelli ◽  
Laurie Ramond ◽  
Arjen Nauta ◽  
...  

With the availability of an increasing number of 3D structures of bacteriophage components, combined with powerful in silico predictive tools, it has become possible to decipher the structural assembly and functionality of phage adhesion devices. In the current study, we examined 113 members of the 936 group of lactococcal siphophages, and identified a number of Carbohydrate Binding Modules (CBMs) in the neck passage structure and major tail protein, on top of evolved Dit proteins, as recently reported by us. The binding ability of such CBM-containing proteins was assessed through the construction of green fluorescent protein fusion proteins and subsequent binding assays. Two CBMs, one from the phage tail and another from the neck, demonstrated definite binding to their phage-specific host. Bioinformatic analysis of the structural proteins of 936 phages reveals that they incorporate binding modules which exhibit structural homology to those found in other lactococcal phage groups and beyond, indicating that phages utilize common structural “bricks” to enhance host binding capabilities. The omnipresence of CBMs in Siphophages supports their beneficial role in the infection process, as they can be combined in various ways to form appendages with different shapes and functionalities, ensuring their success in host detection in their respective ecological niches.


2007 ◽  
Vol 8 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Lada Filonova ◽  
Åsa M. Kallas ◽  
Lionel Greffe ◽  
Gunnar Johansson ◽  
Tuula T. Teeri ◽  
...  

2003 ◽  
Vol 371 (3) ◽  
pp. 1027-1043 ◽  
Author(s):  
Deborah HOGG ◽  
Gavin PELL ◽  
Paul DUPREE ◽  
Florence GOUBET ◽  
Susana M. MARTÍN-ORÚE ◽  
...  

β-1,4-Mannanases (mannanases), which hydrolyse mannans and glucomannans, are located in glycoside hydrolase families (GHs) 5 and 26. To investigate whether there are fundamental differences in the molecular architecture and biochemical properties of GH5 and GH26 mannanases, four genes encoding these enzymes were isolated from Cellvibrio japonicus and the encoded glycoside hydrolases were characterized. The four genes, man5A, man5B, man5C and man26B, encode the mannanases Man5A, Man5B, Man5C and Man26B, respectively. Man26B consists of an N-terminal signal peptide linked via an extended serine-rich region to a GH26 catalytic domain. Man5A, Man5B and Man5C contain GH5 catalytic domains and non-catalytic carbohydrate-binding modules (CBMs) belonging to families 2a, 5 and 10; Man5C in addition contains a module defined as X4 of unknown function. The family 10 and 2a CBMs bound to crystalline cellulose and ivory nut crystalline mannan, displaying very similar properties to the corresponding family 10 and 2a CBMs from Cellvibrio cellulases and xylanases. CBM5 bound weakly to these crystalline polysaccharides. The catalytic domains of Man5A, Man5B and Man26B hydrolysed galactomannan and glucomannan, but displayed no activity against crystalline mannan or cellulosic substrates. Although Man5C was less active against glucomannan and galactomannan than the other mannanases, it did attack crystalline ivory nut mannan. All the enzymes exhibited classic endo-activity producing a mixture of oligosaccharides during the initial phase of the reaction, although their mode of action against manno-oligosaccharides and glucomannan indicated differences in the topology of the respective substrate-binding sites. This report points to a different role for GH5 and GH26 mannanases from C. japonicus. We propose that as the GH5 enzymes contain CBMs that bind crystalline polysaccharides, these enzymes are likely to target mannans that are integral to the plant cell wall, while GH26 mannanases, which lack CBMs and rapidly release mannose from polysaccharides and oligosaccharides, target the storage polysaccharide galactomannan and manno-oligosaccharides.


2007 ◽  
Vol 406 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Lavinia Cicortas Gunnarsson ◽  
Cedric Montanier ◽  
Richard B. Tunnicliffe ◽  
Mike P. Williamson ◽  
Harry J. Gilbert ◽  
...  

Molecular engineering of ligand-binding proteins is commonly used for identification of variants that display novel specificities. Using this approach to introduce novel specificities into CBMs (carbohydrate-binding modules) has not been extensively explored. Here, we report the engineering of a CBM, CBM4-2 from the Rhodothermus marinus xylanase Xyn10A, and the identification of the X-2 variant. As compared with the wild-type protein, this engineered module displays higher specificity for the polysaccharide xylan, and a lower preference for binding xylo-oligomers rather than binding the natural decorated polysaccharide. The mode of binding of X-2 differs from other xylan-specific CBMs in that it only has one aromatic residue in the binding site that can make hydrophobic interactions with the sugar rings of the ligand. The evolution of CBM4-2 has thus generated a xylan-binding module with different binding properties to those displayed by CBMs available in Nature.


1998 ◽  
Vol 180 (22) ◽  
pp. 5921-5927 ◽  
Author(s):  
Randall S. Pegden ◽  
Marilynn A. Larson ◽  
Richard J. Grant ◽  
Mark Morrison

ABSTRACT The adherence of Ruminococcus albus 8 to crystalline cellulose was studied, and an affinity-based assay was also used to identify candidate cellulose-binding protein(s). Bacterial adherence in cellulose-binding assays was significantly increased by the inclusion of either ruminal fluid or micromolar concentrations of both phenylacetic and phenylpropionic acids in the growth medium, and the addition of carboxymethylcellulose (CMC) to assays decreased the adherence of the bacterium to cellulose. A cellulose-binding protein with an estimated molecular mass following sodium dodecyl sulfate-polyacrylamide gel electrophoresis of ∼21 kDa, designated CbpC, was present in both cellobiose- and cellulose-grown cultures, and the relative abundance of this protein increased in response to growth on cellulose. Addition of 0.1% (wt/vol) CMC to the binding assays had an inhibitory effect on CbpC binding to cellulose, consistent with the notion that CbpC plays a role in bacterial attachment to cellulose. The nucleotide sequence of the cbpC gene was determined by a combination of reverse genetics and genomic walking procedures. ThecbpC gene encodes a protein of 169 amino acids with a calculated molecular mass of 17,655 Da. The amino-terminal third of the CbpC protein possesses the motif characteristic of the Pil family of proteins, which are most commonly involved with the formation of type 4 fimbriae and other surface-associated protein complexes in gram-negative, pathogenic bacteria. The remainder of the predicted CbpC sequence was found to have significant identity with 72- and 75-amino-acid motifs tandemly repeated in the 190-kDa surface antigen protein of Rickettsia spp., as well as one of the major capsid glycoproteins of the Chlorella virus PBCV-1. Northern blot analysis showed that phenylpropionic acid and ruminal fluid increase cbpC mRNA abundance in cellobiose-grown cells. These results suggest that CbpC is a novel cellulose-binding protein that may be involved in adherence of R. albus to substrate and extends understanding of the distribution of the Pil family of proteins in gram-positive bacteria.


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