Identification of novel beta-mannan- and beta-glucan-binding modules: evidence for a superfamily of carbohydrate-binding modules

Many glycoside hydrolases, which degrade long-chain carbohydrate polymers. possess distinct catalytic modules and noncatalytic carbohydrate-binding mo dules (CBMs). On the basis of conserved protein secondary structure, we des cribe here the identification and experimental characterization of novel ty pe of mannanase-associated mannan-binding module and also characterization of two CBM family 4 laminarinase-associated beta -glucan-binding modules. T hese modules are predicted to belong to a superfamily of CBMs which include families 4, 16, 17, 22 and a proposed new family, family 27.