Synthetic xylan-binding modules for mapping of pulp fibres and wood sections

Abstract

Background: The complex carbohydrate composition of natural and refined plant material is not known in detail but a matter that is of both basic and applied importance. Qualitative assessment of complex samples like plant and wood tissues requires the availability of a range of specific probes. Monoclonal antibodies and naturally existing carbohydrate binding modules (CBMs) have been used in the past to assess the presence of certain carbohydrates in plant tissues. However, the number of natural CBMs is limited and development of carbohydrate-specific antibodies is not always straightforward. We envisage the use of sets of very similar proteins specific for defined targets, like those developed by molecular evolution of a single CBM scaffold, as a suitable strategy to assess carbohydrate composition. An advantage of using synthetic CBMs lies in the possibility to study fine details of carbohydrate composition within non-uniform substrates like plant cell walls as made possible through minor differences in CBM specificity of the variety of binders that can be developed by genetic engineering.

Immunolocalization and structural variations of xylan in differentiating earlywood tracheid cell walls of Cryptomeria japonica

“…From enzymatic degradation of cell walls using xylanase, Parameswaran and Sinner (1979) and Parameswaran and Liese (1982) also showed the distribution of xylan in cell walls. More recently, cytochemical studies have shown the distribution of xylans in wood cell walls using various immunological probes such as xylanase-gold complexes, antibodies, and carbohydrate binding modules (Awano et al 1998(Awano et al , 2000(Awano et al , 2002Carafa et al 2005;Filonova et al 2007;Hosoo et al 2006;Ruel et al 2006;Vian et al 1986Vian et al , 1992. In particular, Awano et al (1998Awano et al ( , 2000Awano et al ( , 2002 systematically investigated the distribution of xylans (AcGXs) in the cell walls of fibers using various immunological methods in combination with enzyme and chemical treatment of the cell walls.…”

Localization of Cell Wall Polysaccharides in Normal and Compression Wood of Radiata Pine: Relationships with Lignification and Microfibril Orientation

“…Altaner et al (2010) have examined the distribution of heteroxylans in radiata pine (Pinus radiata) by immunoelectron microscopy showing unsubstituted xylans (LM10) in the S1 and S3 layers and more highly substituted xylans (LM11) across all areas of the cell wall except the primary wall. Filonova et al (2007) also demonstrated a generalized distribution of labeled xylan-binding modules across cell walls on Scots pine (Pinus sylvestris) wood sections.…”

Quantitative assessment of xylan distribution across the secondary cell wall layers of Eucalyptus dissolving pulp fibres

“…These are alternatives to antibody probes because they are smaller (e.g. typically <20 kDa vs. ~150 kDa for antibodies) and show specificity for individual carbohydrates (Ding et al 2006;Filonova et al 2007b;Oliveira et al 2015;Pattathil et al 2015). Furthermore, the ease of their production and modification with peptides and fluorescent and gold markers for microscopy is also encouraging (Filonova et al 2007b).…”

“…Cellulose in wood fibre cell walls has been localised by CBMs (Mclean et al 2002;Hildén et al 2003;Daniel et al 2006;Ding et al 2006;Filonova et al 2007a), such as xylan (McCartney et al 2006;Filonova et al 2007b), and mannan (Filonova et al 2007a). McCartney et al (2006) studied the affinity of six different xylan-specific CBMs in binding to primary and secondary cell walls for several dicotyledonous species.…”

“…It was concluded that the variation of CBM specificity for ligands may also be useful for the detection of distinct xylans in the cell wall (McCartney et al 2006). Synthetically engineered xylan-binding CBMs were applied to target xylan molecules in birch and pine wood sections and birch kraft pulp fibres, and Filonova et al (2007b) demonstrated that these kind of CBMs conjugated to fluorescein isothiocyanate (FITC) exhibit higher binding signals in delignified tissues compared to mature (normal) birch and pine wood. The CBMs in the quoted study were conjugated to the fluorescent dye [fluorescein isothiocyanate (FITC)], and the specimens were viewed by fluorescence microscopy.…”