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Lemos, Margarida; Teixeira, J. A.; Мота, М.; Gama, Miguel

doi:10.1023/a:1005691821173

Cited by 21 publications

(3 citation statements)

References 15 publications

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“…A single cellulose binding domain coded as CBD was prepared by enzymatic hydrolysis of fungal cellulases according to the protocol described elsewhere [25]. A crude cellulase preparation (Celluclast, Novo Nordisk) was hydrolysed with papain.…”

Section: Cbd Samplesmentioning

confidence: 99%

Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

Nigmatullin

Lovitt

Wright

et al. 2004

Colloids and Surfaces B: Biointerfaces

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Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs.The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reveals agglomeration of CBD adsorbed on cellulose surface. Despite an increase in surface charge owing to CBD binding to cellulose surface, force profiles are less repulsive for interactions involving, at least, one modified surface. Such changes are attributed to irregularity of the topography of protein surface and non-uniform distribution of surface charges on the surface of modified cellulose.Binding double CBD hybrid protein to cellulose surfaces causes adhesive forces at retraction, whereas separation curves obtained with cellulose modified with single CBD show small adhesion only at high ionic strength. This is possibly caused by the formation of the cross-links between cellulose surfaces in the case of double CBD.

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Section: Cbd Samplesmentioning

confidence: 99%

Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

Nigmatullin

Lovitt

Wright

et al. 2004

Colloids and Surfaces B: Biointerfaces

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show abstract

“…Considering that the cellulosome has its own major cellobiohydrolase (Cel48S) , which like Cel7A depolymerizes cellulose chains processively from the reducing end, we asked what the Cel7A has, and the dispersed Cel48S apparently lacks, that is crucial for synergy with the native cellulosome. Being a strong candidate to make a difference, the cellulose binding module of Cel7A was processed off from the enzyme, and the isolated catalytic module was examined separately (Figure S13). As shown in Figure C, the Cel7A catalytic module is almost identically effective as the intact cellulase, suggesting that synergy with the cellulosome is due to an intrinsic cellobiohydrolase catalytic feature of the Cel7A, independent of interactions from the enzyme’s binding module.…”

Section: Resultsmentioning

confidence: 99%

Processive Enzymes Kept on a Leash: How Cellulase Activity in Multienzyme Complexes Directs Nanoscale Deconstruction of Cellulose

et al. 2021

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Biological deconstruction of polymer materials gains efficiency from the spatiotemporally coordinated action of enzymes with synergetic function in polymer chain depolymerization. To perpetuate enzyme synergy on a solid substrate undergoing deconstruction, the overall attack must alternate between focusing the individual enzymes locally and dissipating them again to other surface sites. Natural cellulases working as multienzyme complexes assembled on a scaffold protein (the cellulosome) maximize the effect of local concentration yet restrain the dispersion of individual enzymes. Here, with evidence from real-time atomic force microscopy to track nanoscale deconstruction of single cellulose fibers, we show that the cellulosome forces the fiber degradation into the transversal direction, to produce smaller fragments from multiple local attacks (“cuts”). Noncomplexed enzymes, as in fungal cellulases or obtained by dissociating the cellulosome, release the confining force so that fiber degradation proceeds laterally, observed as directed ablation of surface fibrils and leading to whole fiber “thinning”. Processive cellulases that are enabled to freely disperse evoke the lateral degradation and determine its efficiency. Our results suggest that among natural cellulases, the dispersed enzymes are more generally and globally effective in depolymerization, while the cellulosome represents a specialized, fiber-fragmenting machinery.

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“…n° 4021050) cellulose fibers were used. CBDs were obtained by the method described in Lemos et al The probes used for inverse chromatography were n -hexane, n -heptane, n -octane, and n -decane, chloroform, tetrahydrofuran (THF), diethyl ether, acetone, and ethyl acetate; all chemicals were of the highest purity available.…”

Section: Methodsmentioning

confidence: 98%

Studies on the Cellulose-Binding Domains Adsorption to Cellulose

et al. 2004

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Cellulose-binding domains (CBD) are modular peptides, present in many glycanases, which anchor these enzymes to the substrate. In this work, the effect of CBD adsorption on the surface properties of a model cellulose, Whatman CF11, was studied. The methods applied include inverse gas chromatography (IGC), ESCA, X-ray diffraction, and scanning electron microscopy (SEM). The CBD partition affinity (0.85 L/g) was calculated from adsorption isotherms. However, true adsorption equilibrium does not exist, since CBDs are apparently irreversibly adsorbed to the fibers. Both IGC and ESCA showed that fibers with adsorbed CBD have a lower acidic character and also a slightly higher affinity toward aliphatic molecules. This may however be a consequence of an increased surface area, a hypothesis that is supported by microscopic observations. The crystallinity index was not affected by CBD treatment.

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Untitled

Cited by 21 publications

References 15 publications

Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

Processive Enzymes Kept on a Leash: How Cellulase Activity in Multienzyme Complexes Directs Nanoscale Deconstruction of Cellulose

Studies on the Cellulose-Binding Domains Adsorption to Cellulose

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