FIG 3.

Binding of the bgp mutant to heparin is significantly reduced. Plate wells were coated with purified heparin or chondroitin sulfate C (5 mg/ml) or PBS. ³⁵S-labeled B31 5A4 (WT), bgpmut, and bgpcomp strains were added, and binding was quantified by scintillation counting. (A) Buffer-only-treated (control) wells showed low nonspecific binding by each strain. (B) Adherence to heparin was significantly reduced in the mutant strain compared to WT and bgpcomp strains. (C) Overall binding of all strains to chondroitin sulfate C was unaffected by Bgp expression and was comparable to that seen in buffer control wells as shown in panel A. After subtracting the background count for empty well from all treated-well radiolabel counts determined by scintillation counting, the adjusted binding was divided by the total bacterial input label for each strain, and the percent binding was calculated. Each bar represents the mean ± SD for quadruplicate samples. Statistical significance (***, P ≤ 0.001) was determined by the Student t test for comparison of samples with unequal variances (ns, not significant).