Stable linker peptides for a cellulose-binding domain-lipase fusion protein expressed in Pichia pastoris

Fusion proteins composed of a cellulose-binding domain from Neocallimastix patriciarum cellulase A and Candida antarctica lipase B were constructed us ing different linker peptides. The aim was to create proteolytically stable linkers that were able to join the functional modules without disrupting t heir function. Six fusion variants containing linkers of 4-44 residues were expressed in Pichia pastoris and analysed. Three variants were found to be stable throughout 7-day cultivations. The cellulose-binding capacities of fusion proteins containing short linkers were slightly lower compared with those containing long linkers. The lipase-specific activities of all varian ts, in solution or immobilized on to cellulose, were equal to that of the w ildtype lipase.