Abstract

The complex carbohydrate composition of natural and processed plant material is not known in detail and a matter 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 frequently been used to demonstrate 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 and microdistribution in plant substrates. 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 through minor differences in CBM specificity of the variety of binders that can be developed by genetic engineering. A panel of synthetic xylan-binding CBMs, previously selected from a molecular library based on the scaffold of CBM4-2 from xylanase Xyn10A of Rhodothermus marinus, were used in this study to map xylan in poplar, birch and pine wood sections. Fluorescence microscopy showed the wild type CBM4-2 and evolved modules to bind differentially to wood sections and processed fibres. Differences were observed in the staining patterns suggesting not only variations in xylan distribution in the native wood materials but also that these modules also have preferential xylan-binding properties. The staining stability also varied between the CBMs, the most stable staining being obtained with one (X-2) of the synthetic modules. Prior treatment (e.g. alkali) of wood materials resulted in altered signal intensities, thereby also demonstrating the potential application of engineered CBMs as analytical tools for quality assessment of diverse plant material processes. In more recent work we are assessing the ability of both fucosylated and non-fucosylated specific xyloglucan-CBMs selected from the same library with the monoclonal antibody CCRC-M1 against fucosylated xyloglucan and comparing the specificity and labeling patterns in developing and mature poplar cells. Studies show the usefulness of synthetic binding modules as specific probes in analysis of carbohydrates in wood and fibre materials

Published in

Conference

Funcfiber 2008; International Symposium on the biology and Biotechnology of wood

SLU Authors

• Stålhandske, Lada

  • Department of Forest Products, Swedish University of Agricultural Sciences
    

• Daniel, Geoffrey

  • Department of Forest Products, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/17765