Synthesis of Epitope-Targeting Antibody Based on Native Protein–Protein Interactions for Ftsz Filamentation Suppressor

Phage display and biopanning is a powerful tool for generating binding molecules for a specific target. However, the selection process based on binding affinity provides no assurance for the antibody’s affinity to the target epitope. In this study, we propose a molecular-evolution approach guided by native protein–protein interactions to generate epitope-targeting antibodies. The binding-site sequence in a native protein was grafted into a complementarity-determining region (CDR) in the antibody, and a nonrelated CDR loop (in the grafted antibody) was randomized by phage display techniques. In this construction of antibodies by integrating graft and evolution technology (CAnIGET method), suitable grafting of the functional sequence weakly functionalized the antibody, and the molecular-evolution approach enhanced the binding function to inhibit the native protein–protein interactions. Antibody fragments with an affinity for filamenting temperature-sensitive mutant Z (FtsZ) were constructed and completely inhibited the polymerization of FtsZ. Consequently, the expression of these fragments drastically decreased the cell division rate. We demonstrate the potential of the CAnIGET method with the use of native protein–protein interactions for steady epitope-specific evolutionary engineering.