Model cellulose films exposed to H. insolens glucoside hydrolase family 45 endo-cellulase—the effect of the carbohydrate-binding module

Eriksson, Jan Christer; Malmsten, Martin; Tiberg, Fredrik; Callisen, Thomas H.; Damhus, Ture; Johansen, Katja Salomon

doi:10.1016/j.jcis.2004.10.042

Cited by 31 publications

(29 citation statements)

References 44 publications

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“…A VAST search with D1 alone combined with bibliographical searches identified 4 structurally related families involved in polysaccharide recognition: the plant defense protein barwin (15), GH45 (3,(16)(17)(18), plant expansins (3), and family 2 of peptidoglycan lytic transglycosylases (LT), exemplified by MltA (19 (18)]. These proteins are quite divergent: pairwise sequence alignments with D1 range from 8% to 35% identity for most pairs (Table S2).…”

Section: Exlx1mentioning

confidence: 99%

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Kerff

Amoroso

Herman

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

183

291

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We solved the crystal structure of a secreted protein, EXLX1, encoded by the yoaJ gene of Bacillus subtilis. Its structure is remarkably similar to that of plant ␤-expansins (group 1 grass pollen allergens), consisting of 2 tightly packed domains (D1, D2) with a potential polysaccharide-binding surface spanning the 2 domains. Domain D1 has a double-␤-barrel fold with partial conservation of the catalytic site found in family 45 glycosyl hydrolases and in the MltA family of lytic transglycosylases. Domain D2 has an Ig-like fold similar to group 2/3 grass pollen allergens, with structural features similar to a type A carbohydratebinding domain. EXLX1 bound to plant cell walls, cellulose, and peptidoglycan, but it lacked lytic activity against a variety of plant cell wall polysaccharides and peptidoglycan. EXLX1 promoted plant cell wall extension similar to, but 10 times weaker than, plant ␤-expansins, which synergistically enhanced EXLX1 activity. Deletion of the gene encoding EXLX1 did not affect growth or peptidoglycan composition of B. subtilis in liquid medium, but slowed lysis upon osmotic shock and greatly reduced the ability of the bacterium to colonize maize roots. The presence of EXLX1 homologs in a small but diverse set of plant pathogens further supports a role in plant-bacterial interactions. Because plant expansins have proved difficult to express in active form in heterologous systems, the discovery of a bacterial homolog opens the door for detailed structural studies of expansin function.family 45 endoglucanase ͉ lytic transglycosylase ͉ peptidoglycan ͉ plant cell wall ͉ plant-microbe interactions B acterial and plant cell walls have similar functions but distinctive structures. Bacterial peptidoglycan forms a network of linear polysaccharide strands of alternating Nacetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues cross-linked by short polypeptides. As a giant bag-shaped sacculus, peptidoglycan expands via the action of endopeptidases, amidases, and lytic transglycosylases that cleave covalent bonds and allow insertion of new subunits (1). In contrast, the growing plant cell wall is formed from a scaffold of cellulose microfibrils tethered together by branched glycans such as xyloglucan or arabinoxylan that bind noncovalently to cellulose surfaces. The cellulose-hemicellulose network enlarges via polymer slippage or ''creep,'' mechanically powered by turgorgenerated forces in the cell wall and catalyzed by expansins and other wall-loosening agents (2).Expansins are known principally from plants where they function in cell enlargement and other developmental events requiring cell wall loosening (3). Canonical expansins are small proteins (Ϸ26 kDa, Ϸ225 aa) consisting of 2 compact domains: D1 has a fold similar to that of family 45 glycosyl hydrolases (GH45), and D2 has a ␤-sandwich fold. Expansins facilitate cell wall creep without breakdown of wall polymers (3-5). Plant expansins consist of 2 major families: ␣-expansins, which preferentially loosen the cell walls of dicots compa...

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Section: Exlx1mentioning

confidence: 99%

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Kerff

Amoroso

Herman

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

183

291

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“…More information on this enzyme and details of its preparation can be found in [11]. After incubation of the enzyme with DyLight 633™ (Thermo ScientiWc, Rockford, IL, USA) for 1 h (standing) in 0.05 M pH 8.5 borate buVer at room temperature, excess Xuorophore was removed by centrifugation (4,700 rpm, 15 min, multiple times, until a clear supernatant solution was obtained) using a Vivaspin ultraWltration spin column (5 K MWCO, Sartorius Stedim GmbH, Goettingen, Germany).…”

Section: Enzymatic Hydrolysismentioning

confidence: 99%

Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

Thygesen

Hidayat

Johansen

et al. 2010

J Ind Microbiol Biotechnol

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The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes and they are known to be more susceptible to various forms of degradation such as acid hydrolysis. Traditionally the cellulose within these regions has been assumed to be amorphous, but in this study it is shown by use of polarized light microscopy that dislocations are birefringent. This indicates that they have a crystalline organisation. Dislocations may be entry points for endoglucanases. Using a fluorescent labelled endoglucanase combined with confocal fluorescence microscopy, it is shown that the enzyme selectively binds to dislocations during the initial phase of the hydrolysis. Using a commercial cellulase mixture on hydrothermally treated wheat straw, it was found that the fibres were cut into segments corresponding to the sections between the dislocations initially present, as has previously been observed for acid hydrolysis of softwood pulps. The results indicate that dislocations are important during the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels.

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“…To date, cellulose model films have been prepared from either nanocellulose, or cellulose derivatives using two main approaches: Langmuir-Blodgett (LB) deposition14 and spin coating1516. The relative performances of these techniques have been reviewed by Kontturi11.…”

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confidence: 99%

“…measured the adsorption kinetics of H. insolens , a cellulase, on thin cellulose films in terms of adsorption mass and film thickness using ellipsometry. They reported full enzyme coverage on cellulose forming a monolayer 25 Å thick adsorbed at Γ max = 5.5 mg/m 2 ; the dry cellulose films were 300 Å thick with a roughness of 50 Å and swelled to 820 Å once hydrated16.…”

mentioning

confidence: 99%

“…While SPR and QCM offer quantification of the adsorption kinetics in real time, atomic force microscopy (AFM), ellipsometry16 and reflectometry (X-ray and neutron) have emerged as powerful techniques to probe the morphology of biomolecules at liquid-solid interfaces. Of those techniques, neutron reflectometry (NR) is especially attractive because of its sensitivity to isotopic contrast, specifically between the number density of deuterium ( 2 H) and the light isotope of hydrogen ( 1 H), between either the biomolecule or the substrate.…”

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confidence: 99%

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Smooth deuterated cellulose films for the visualisation of adsorbed bio-macromolecules

Raghuwanshi

Raverty

et al. 2016

Sci Rep

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Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating. The resulting film was regenerated into deuterated cellulose by exposure to acidic vapour. A common enzyme, horseradish peroxidase (HRP), was adsorbed from solution onto the deuterated cellulose films and visualized by NR. The scattering length density contrast of the deuterated cellulose enabled accurate visualization and quantification of the adsorbed HRP, which would have been impossible to achieve with non-deuterated cellulose. The procedure described enables preparing deuterated cellulose films that allows differentiation of cellulose and non-deuterated bio-macromolecules using NR.

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Model cellulose films exposed to H. insolens glucoside hydrolase family 45 endo-cellulase—the effect of the carbohydrate-binding module

Cited by 31 publications

References 44 publications

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Crystal structure and activity of Bacillus subtilis YoaJ (EXLX1), a bacterial expansin that promotes root colonization

Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

Smooth deuterated cellulose films for the visualisation of adsorbed bio-macromolecules

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