Team:Warsaw

We have developed a system allowing to search for antibodies with new specificities or screen protein libraries in order to generate interactors for a given bait. Our system changes a protein sequence to maximize its interaction with a given partner. Proteins with modified sequences are then directed to the bacterial outer membrane, where the best interactors are selected. Protein presented on the cell surface is fused with part of β-lactamase protein, while its bait is fused with the complementing part of the enzyme and added to medium. The stronger the interaction between proteins of interest, the more efficient the binding of the two halves of β-lactamase, leading to resistance to ampicillin and survival. Cells expressing less interacting variants die as they don't achieve sufficient complementation of the reporter enzyme. This allows us to select strains producing interactors for any given bait.