Carbohydrate Binding Module 6 (CBM6); many are appended to glycoside hydrolase (GH) family 11 and GH43 xylanase domains. This family includes carbohydrate binding module 6 (CBM6) domains that are appended mainly to glycoside hydrolase (GH) family domains, including GH3, GH11, and GH43 domains. These CBM6s are non-catalytic carbohydrate binding domains that facilitate the strong binding of the GH catalytic modules with their dedicated, insoluble substrates. Examples of proteins having CMB6s belonging to this family are Microbispora bispora GghA, a 1,4-beta-D-glucan glucohydrolase (GH3); Clostridium thermocellum xylanase U (GH11), and Penicillium purpurogenum ABF3, a bifunctional alpha-L-arabinofuranosidase/xylobiohydrolase (GH43). GH3 comprises enzymes with activities including beta-glucosidase (hydrolyzes beta-galactosidase) and beta-xylosidase (hydrolyzes 1,4-beta-D-xylosidase). GH11 family comprises enzymes with xylanase (endo-1,4-beta-xylanase) activity which catalyze the hydrolysis of beta-1,4 bonds of xylan, the major component of hemicelluloses, to generate xylooligosaccharides and xylose. GH43 includes beta-xylosidases and beta-xylanases, using aryl-glycosides as substrates. CBM6 is an unusual CBM as it represents a chimera of two distinct binding sites with different modes of binding: binding site I within the loop regions and binding site II on the concave face of the beta-sandwich fold.

Carbohydrate binding module (family 6).

Cellulose Binding Domain Type IV.

Type I dockerin repeat domain. Bacterial cohesin domains bind to a complementary protein domain named dockerin, and this interaction is required for the formation of the cellulosome, a cellulose-degrading complex. The cellulosome consists of scaffoldin, a noncatalytic scaffolding polypeptide, that comprises repeating cohesion modules and a single carbohydrate-binding module (CBM). Specific calcium-dependent interactions between cohesins and dockerins appear to be essential for cellulosome assembly. This subfamily represents type I dockerins, which are responsible for anchoring a variety of enzymatic domains to the complex.

Carbohydrate Binding Module 6 (CBM6); appended to glycoside hydrolase (GH) domains, including GH5 (cellulase). This family includes carbohydrate binding module 6 (CBM6) domains that are appended to several glycoside hydrolase (GH) domains, including GH5 (cellulase) and GH16, as well as to coagulation factor 5/8 carbohydrate-binding domains. CBM6s are non-catalytic carbohydrate binding domains that facilitate the strong binding of the GH catalytic modules with their dedicated, insoluble substrates. The CBM6s are appended to GHs that display a diversity of substrate specificities. For some members of this family information is available about the specific substrates of the appended GH domains. It includes the CBM domains of various enzymes involved in cell wall degradation including, an extracellular beta-1,3-glucanase from Lysobacter enzymogenes encoded by the gluC gene (its catalytic domain belongs to the GH16 family), the tandem CBM domains of Pseudomonas sp. PE2 beta-1,3(4)-glucanase A (its catalytic domain also belongs to GH16), and a family 6 CBM from Cellvibrio mixtus Endoglucanase 5A (CmCBM6) which binds to the beta1,4-beta1,3-mixed linked glucans lichenan, and barley beta-glucan, cello-oligosaccharides, insoluble forms of cellulose, the beta1,3-glucan laminarin, and xylooligosaccharides, and the CBM6 of Fibrobacter succinogenes S85 XynD xylanase, appended to a GH10 domain, and Cellvibrio japonicas Cel5G appended to a GH5 (cellulase) domain. GH5 (cellulase) family includes enzymes with several known activities such as endoglucanase, beta-mannanase, and xylanase, which are involved in the degradation of cellulose and xylans. GH16 family includes enzymes with lichenase, xyloglucan endotransglycosylase (XET), and beta-agarase activities. CBM6 is an unusual CBM as it represents a chimera of two distinct binding sites with different modes of binding: binding site I within the loop regions and binding site II on the concave face of the beta-sandwich fold. For CmCBM6 it has been shown that these two binding sites have different ligand specificities.

CrystalStructure of a Family 6 Carbohydrate-Binding Module from Clostridium cellulolyticum in complex with xylose [Ruminiclostridium cellulolyticum]

R.flavefaciens' third ScaB cohesin in complex with a group 1 dockerin [Ruminococcus flavefaciens FD-1]

ChainA, CBM6 [Acetivibrio thermocellus],1UXX_X Chain X, Xylanase U [Acetivibrio thermocellus]

Unboundstructure of CsCBM6-3 from Clostridium stercorarium [Thermoclostridium stercorarium]

Bindingsub-site dissection of a family 6 carbohydrate-binding module by X-ray crystallography and isothermal titration calorimetry [Thermoclostridium stercorarium],1UY2_A Binding sub-site dissection of a family 6 carbohydrate-binding module by X-ray crystallography and isothermal titration calorimetry [Thermoclostridium stercorarium],1UY3_A Binding sub-site dissection of a family 6 carbohydrate-binding module by X-ray crystallography and isothermal titration calorimetry [Thermoclostridium stercorarium],1UY4_A Binding sub-site dissection of a family 6 carbohydrate-binding module by X-ray crystallography and isothermal titration calorimetry [Thermoclostridium stercorarium]

Xylanase/beta-glucanase OS=Ruminococcus flavefaciens OX=1265 GN=xynD PE=3 SV=2

Endo-1,4-beta-xylanase A OS=Thermoclostridium stercorarium OX=1510 GN=xynA PE=1 SV=2

Endo-1,4-beta-xylanase A OS=Thermoclostridium stercorarium OX=1510 GN=xynA PE=1 SV=2

Endo-1,4-beta-xylanase Z OS=Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372) OX=203119 GN=xynZ PE=1 SV=3

Probable pectate lyase C OS=Aspergillus flavus (strain ATCC 200026 / FGSC A1120 / IAM 13836 / NRRL 3357 / JCM 12722 / SRRC 167) OX=332952 GN=plyC PE=3 SV=1