Figure 3.

Association and dissociation constants for interactions between Zα and Z-DNA polymer, compared with that of mAb Z22 Fab (22). The binding was determined using surface plasmon resonance (BIAcore, Pharmacia Biosensor) and are labeled in RU, or response units, which measure the mass bound to the surface of a sensor chip. The equilibrium constant K_D for Zα (A) and Z22 Fab (B) are shown. The association rate (k_on) was measured over a 180-s period, and the dissociation rate (k_off) was over a 200-s time frame. Neither protein gave measurable association when a biotinylated 400-bp mixed sequence B-DNA fragment was attached to the sensor chip.