FIGURE 1.

Schematic representation of the A. cellulolyticus cellulosome. Type I dockerin modules located in A. cellulolyticus cellulosomal enzymes bind reiterated cohesin modules located in the primary scaffoldin ScaA. ScaB plays the role of an adaptor scaffoldin with its cohesins binding the type II dockerin of ScaA. ScaB also contains a type I dockerin that specifically binds the complementary type I cohesins of the anchoring scaffoldin ScaC. The entire complex is tethered to the bacterial cell surface via the resident SLH module of ScaC. ScaA also contains a carbohydrate-binding module and a GH9 catalytic module. The structures of the ScaB dockerin in complex with the third cohesin of ScaC, solved here, are highlighted with a black dot.