A plasmid toolbox for the easy autodisplay of recombinant proteins and its optimization

Surface display of proteins on bacteria bears several advantages for binding studies, library screening or enzyme inhibitor testing. Here, we present a set of plasmids for autodisplay-based surface expression of recombinant proteins, named Autodisplay-ToolBox (ATB). In this set, crucial parts as required for autodisplay, including promotor, SP, linker and β-barrel can be combined in varying permutations to find the best combination for a certain protein. The plasmids can be applied individually or in library approaches, enabling optimization of surface display in a single step. By such a library approach, the activity of surface-displayed β-glucosidase (β-Gluc) is increased by a factor of 4.9, the activity of a laccase (CotA) by a factor of 4.7 and the binding capacity of the surface-displayed nucleotide binding domain of human HCN2 channel (HCN2-CNBD) by a factor of 10.3. It is shown that the ATB can be used in different strains of E. coli as well as in Pseudomonas putida. The aim is to provide a selection of plasmids, accessible by Addgene, that every scientist can use for their own protein, either individually based on personal preferences, structural features, etc., or as a library, as shown here for three different examples.