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.
Dockerin repeat domain. Dockerins are modules in the cellulosome complex that often anchor catalytic subunits by binding to cohesin domains of scaffolding proteins. Three types of dockerins and their corresponding cohesin have been described in the literature. This alignment models two consecutive dockerin repeats, the functional unit.
Carbohydrate esterase 2 N-terminal. This is the N-terminal beta-sheet domain with jelly roll topology found in CE2 acetyl-esterase from the bacterium Clostridium thermocellum. This enzyme displays dual activities, it catalyses the deacetylation of plant polysaccharides and also potentiates the activity of its appended cellulase catalytic module through its noncatalytic cellulose binding function. This N-terminal jelly-roll domain appears to extend the substrate/cellulose binding cleft of the catalytic domain in C.thermocellum.
Dockerin type I repeat. The dockerin repeat is the binding partner of the cohesin domain pfam00963. The cohesin-dockerin interaction is the crucial interaction for complex formation in the cellulosome. The dockerin repeats, each bearing homology to the EF-hand calcium-binding loop bind calcium.