FIGURE 2.

Hb subunits possess high affinity for bacterial LPS. S. minnesota LPS was immobilized on an HPA sensor chip. rHbα and rHbβ at 0.1, 0.25, 0.5, and 0.75 μm in HBS were individually injected over the ligand-immobilized chip surface at a flow rate of 30 μl/min. Data were fitted to a 1:1 Langmuir binding model using the separate fit module of the BIAevaluation software (version 4.1). Sensorgrams for the interaction of rHbα (A) and rHbβ (B) with LPS are shown in black. The red lines represent the corresponding fits. Plots of residuals corresponding to the differences between the experimental and best-fit curves are shown in the lower panel. RU, response units. C, kinetic parameters for binding of rHbα and rHbβ to the various ligands.