CONSTRUCTION AND FUNCTIONAL-CHARACTERIZATION OF A SINGLE-CHAIN FV ANTIBODY-BINDING TO THE PLANT HORMONE ABSCISIC-ACID

The VH and VK genes coding for the variable regions of the monoclonal antibody 15-I-C5 to abscisic acid were isolated by molecular cloning a nd connected by a linker to allow translation of the single chain Fv f usion protein gene. This was expressed in E. coli either as a free pep tide secreted into the periplasmic space or as a fusion protein with p rotein g3 of the single strand phage. Binding to abscisic acid, either by free scFv or by an anti-ABA scFv displaying fd phage, was shown by ELISA. Specificity to ABA comparable to the binding properties of the complete antibody was verified by competition ELISA. A comparison of the relative affinity to ABA of the scFv and the complete antibody was carried out using competition ELISA with anti-ABA scFv display phage.