Fig. 4.

Binding of DBL4ζ mutants to human IgM by SPR.

SPR sensograms showing wild type and mutant DBL4ζ recombinant proteins binding to human IgM. Proteins were diluted two-fold starting at 600 nM. All six dilutions were flowed at the rate of 25 μl/min (200 s contact time and 200 s dissociation) and regenerated with Glycine-HCl (pH 2.5). Values obtained using an uncoated lane were subtracted to give specific binding data. All of the recombinant proteins that contain the R1764E mutation did not fully dissociate, suggesting that some protein may be interacting non-specifically to the chip. Two independent experiments were carried out with similar results.