title: Investigation of the binding properties of a multi-modular GH45 cellulase using bioinspired model assemblies.
abstract: BACKGROUND
  Enzymes degrading plant biomass polymers are widely used in biotechnological applications. Their efficiency can be limited by non-specific interactions occurring with some chemical motifs. In particular, the lignin component is known to bind enzymes irreversibly. In order to determine interactions of enzymes with their substrates, experiments are usually performed on isolated simple polymers which are not representative of plant cell wall complexity. But when using natural plant substrates, the role of individual chemical and structural features affecting enzyme-binding properties is also difficult to decipher.
  
  
  RESULTS
  We have designed and used lignified model assemblies of plant cell walls as templates to characterize binding properties of multi-modular cellulases. These three-dimensional assemblies are modulated in their composition using the three principal polymers found in secondary plant cell walls (cellulose, hemicellulose, and lignin). Binding properties of enzymes are obtained from the measurement of their mobility that depends on their interactions with the polymers and chemical motifs of the assemblies. The affinity of the multi-modular GH45 cellulase was characterized using a statistical analysis to determine the role played by each assembly polymer. Presence of hemicellulose had much less impact on affinity than cellulose and model lignin. Depending on the number of CBMs appended to the cellulase catalytic core, binding properties toward cellulose and lignin were highly contrasted.
  
  
  CONCLUSIONS
  Model assemblies bring new insights into the molecular determinants that are responsible for interactions between enzymes and substrate without the need of complex analysis. Consequently, we believe that model bioinspired assemblies will provide relevant information for the design and optimization of enzyme cocktails in the context of biorefineries.
authors.affiliation: UMR0614, Fractionnement des AgroRessources et Environnement, INRA, 2 esplanade Roland-Garros, 51100 Reims, France ; UMR0614, Fractionnement des AgroRessources et Environnement, University of Reims Champagne Ardenne, 2 esplanade Roland-Garros, 51100 Reims, France.
authors.forename: Monica
authors.initials: M
authors.lastname: Fong
authors.affiliation: UMR1163, Biodiversité et Biotechnologie Fongiques, INRA, 13288 Marseille, France ; UMR1163, Biodiversité et Biotechnologie Fongiques, Aix Marseille Université, 13288 Marseille, France ; UMR1163, Biodiversité et Biotechnologie Fongiques, Polytech'Marseille, 13288 Marseille, France.
authors.forename: Jean-Guy
authors.initials: JG
authors.lastname: Berrin
authors.affiliation: UMR0614, Fractionnement des AgroRessources et Environnement, INRA, 2 esplanade Roland-Garros, 51100 Reims, France ; UMR0614, Fractionnement des AgroRessources et Environnement, University of Reims Champagne Ardenne, 2 esplanade Roland-Garros, 51100 Reims, France.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Paës
keywords: Affinity; Carbohydrate-binding module; Cellulase; Interaction; Lignocellulose; Model assemblies; Modularity