Molecular arrangement of adsorbed fibrinogen molecules characterized by specific monoclonal antibodies and a surface plasmon resonance sensor

The exploitation of surface plasmon resonance optical sensor for the study of the accessibility of distinct domains of immobilized fibrinogen molecule s and the evaluation of the fibrinogen arrangement is reported. By investig ation of the interactions of sensor surface-bound fibrinogen with various s pecific monoclonal antibodies it has been found that density, orientation, and accessibility of the individual fibrinogen domains of surface-bound fib rinogen depend on the concentration of fibrinogen in solution during the ad sorption process. At low fibrinogen surface density the majority of molecul es seem to be adsorbed side-on (lying on the surface). At high fibrinogen d ensity the molecules are adsorbed end-on (standing on the surface). The exp erimental data suggest that the distal ends of the (adsorbed) fibrinogen mo lecule (containing polymerisation sites) are oriented anti-parallel to each other, proving off-axis location of the distal end domains. (C) 1998 Elsev ier Science S.A. All rights reserved.