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

• 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 CBMs (carbohydrate-binding modules) has not been extensively explored. Here, we report the engineering of a CBM, CBM42 from the Rhodothermits marinus xylanase Xyn10A, and the identification of the X-2 variant. As compared with the wildtype protein, this engineered module displays higher specificity for the polysaccharide xylan, and a lower preference for binding xylo-oligomers rather than binding the natural decorated polysaccharide. The mode of binding of X-2 differs from other xylan-specific CBMs 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.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

thermodynamics

molecular engineering

carbohydrate-binding module

aromatic residue

binding specificity

xylan

aromatic residue; binding specificity; carbohydrate-binding module; molecular engineering; thermodynamics; xylan

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)