Differential interactions of phytochrome A (Pr vs. Pfr) with monoclonal antibodies probed by a surface plasmon resonance technique.

Phytochromes are red- and far-red light-reversible photoreceptors for photomorphogenesis in plants. Phytochrome A is a dimeric chromopeptide that mediates very low fluence and high irradiance responses. To analyze the surface properties of phytochrome A (phyA), the epitopes of 21 anti-phyA monoclonal antibodies were determined by variously engineered recombinant phyA proteins and the dissociation constants of seven anti-phyA monoclonal antibodies with phyA were measured using a surface plasmon resonance (SPR)-based resonant mirror biosensor (IAsys).