Novel xylan-binding properties of an engineered family 4 carbohydrate-binding module

Lavinia Cicortas Gunnarsson , Cedric Montanier , Richard B Tunnicliffe , Mike P Williamson , Harry J Gilbert , Eva Nordberg Karlsson , Mats Ohlin (1)

1 Dept. of Immunotechnology

Molecular engineering of ligand-binding proteins is commonly used for identification of variants that display novel specificities. Using this approach to introduce novel specificities into carbohydrate-binding modules has not been extensively explored. Here, we report the engineering of a carbohydrate-binding module, CBM4-2 from the Rhodothermus marinus xylanase Xyn10A, and the identification of the X-2 variant. As compared to the wild type protein, this engineered module displays higher specificity for the polysaccharide xylan, and a lower preference for binding xylooligomers rather than binding the natural decorated polysaccharide. The mode of binding of X-2 differs from other xylan-specific carbohydrate-binding modules in that it only has one aromatic residue in the binding site that can make hydrophobic interactions with the sugar rings of the ligand. The evolution of CBM4-2 has thus generated a xylan-binding module with different binding properties to those displayed by CBMs available in Nature.

Mots clés: Life Sciences

Domaines: Autre [q-bio.OT]

Lavinia Cicortas Gunnarsson, Cedric Montanier, Richard B Tunnicliffe, Mike P Williamson, Harry J Gilbert, et al.. Novel xylan-binding properties of an engineered family 4 carbohydrate-binding module. Biochemical Journal, 2007, 406 (2), pp.209-214. ⟨10.1042/BJ20070128⟩. ⟨hal-00478742⟩