Carbohydrate binding module

Ofir, K. Berdichevsky, Y. Benhar, I. Azriel-Rosenfeld, R. Lamed, R. Barak, Y. Bayer, E. A. Morag, E., Versatile protein microarray based on carbohydrate-binding modules, Proteomics 2005, 5, 1806-1814... 

CARBOHYDRATE BINDING MODULES AND THE ATTACK OF GLYCOSIDASES ON INSOLUBLE SUBSTRATES... 

Many glycosidases which attack insoluble or partly soluble polysaccharides have a modular construction, in which catalytic domains and carbohydrate binding modules (CBMs) are produced in the same polypeptide. Although there may be occasional exceptions, the main function of these domains appears to be to increase the local concentration of enzyme by loosely absorbing the enzyme to the substrate. CBMs have been classified into families on the basis of amino acid sequence, like the catalytic domains and are on CAZy, the continuously updated website in summer 2007 there were 49 families. Early work had concentrated on the cellulose binding domains (CBDs) previous classifications had referred to CBM (or CBD) Types and used Roman numerals and, to concur with this usage, CBM Families 1-13 are the same as CBM Types 1-XIII. 

The R modules are not carbohydrate-binding modules, but appear to be the opposite. Direct atomic force microscopy (AFM) measurements found that polymannuronan bound more tightly to the AlgE4 A subunit than to the AR holoenzyme," and that the isolated R module did not bind polymannuronate at all. From the various force-extension curves it is possible to calculate the... 

With the exception of carbohydrate-binding modules attached to glycosi-dases, the book does not cover those interactions of carbohydrates with proteins that do not lead to covalency changes. The thinking behind the omission is that the interactions are weak and often polyvalent, and that the free energy changes involved are below the resolution of physical organic chemistry, even if detailed qualitative descriptions of some interactions are... 

The cost of enzyme preparations has been decreasing in recent years however, it continues to affect considerably the price of ethanol obtained from cellulosic raw materials. Increased enzymatic hydrolysis efficiency is one way to reduce the enz)me cost in bioethanol production. Another method is enzyme recycle and reuse. Immobilization of biocatalysts allows for their economic reuse and development of continuous bioprocess. Although immobilization poses problems of substrate accessibility and binding for most endo- and exocellulases, P-glucosidase exhibits characteristics amenable to immobilization, such as activity on soluble substrates and the lack of a carbohydrate-binding module. Among the possible approaches, immobilization of (J-glucosidase is one prospective solution to the problem. 

Both enzymes have a family 1 CBM however, they differ in that the carbohydrate binding module is N-terminal in FaeA and C-terminal in FaeB (Fig 1). This situation mirrors that of Cel6A (N-terminal CBM) and Cel7A (C-terminal CBM) of T. reesei. The... 

Boraston, A.B. et al.. Carbohydrate-binding modules Diversity of structme and function, in Recent Advances in Carbohydrate Bioengineering, Svenson, B., Ed., The Royal Society of Chemistry, Cambridge, U.K., 1999, p. 202. 

Enhancing the Catafytic Activity of Xylanase by Fusing the Carbohydrate Binding Module... 

Yet another important outcome of the CAZy classification scheme is the recognition that many carbohydrate-degrading enzymes are multimodular, consisting of a single polypeptide chain with independently folding structural elements fulfilling diverse roles. Examples of such modules include catalytic, structural, protein-protein interaction, and carbohydrate-binding modules, which may be connected with defined linker sequences (28,34). Consideration of carbohydrase modularity is thus essential to fully understand the catalytic function of these proteins. 

Clostridium thermocellum s cellulosome. CBM carbohydrate-binding module (Based on Gilbert 2007)... 

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