Binding of recombinant A domain isoypes I – VII to immobilized fibrinogen and elastin. Microtitre dishes were coated with human fibrinogen (a) or human aortic elastin (b). Wells were blocked and then incubated with recombinant A domain proteins isotype I (closed squares), isotype II (closed circles), isotype III (open squares), isoype IV (open circles), isoype V (closed triangles), isoype VI (open diamonds), and isoype VII (open triangles) at the indicated concentrations. Bound A domain proteins were detected by incubation with mouse anti-hexahistidine monoclonal antibody 7E8, then HRP-conjugated goat anti-mouse IgG antibodies followed by TMB substrate. Graphs are representative of three separate experiments.