AN 02 r DNP - hapten unbinding forces studied by molecular dynamics atomic force microscopy simulations

Ž . Unbinding forces of a spin-labeled dinitrophenyl DNP hapten from the monoclonal antibody AN02 F fragment have ab Ž . been studied by molecular dynamics atomic force microscopy AFM simulations. In our nanosecond simulations, unbinding was enforced by pulling the hapten molecule out of the binding pocket. From the simulations unbinding forces of the complex have been determined as a function of pulling velocity. Considering activated unbinding and frictional forces, we used a simple model to extrapolate the unbinding forces to the millisecond timescale of single molecule AFM unbinding experiments. For such experiments the simulations suggest an unbinding force of 60"30 pN. q 1999 Elsevier Science B.V. All rights reserved.