FIGURE 2.

Binding of HufH18–20/Fc to sialylated N. gonorrhoeae: effect of human-to-chimpanzee mutations in HufH domain 20. A, amino acid sequence comparison of human and chimpanzee fH domains 20 (fH20). Identical amino acid residues are denoted by dots. B, binding to sialylated gonococcal strains 252 and F62 by HufH18–20/Fc constructs that separately contained the indicated chimpanzee fH domain 20 point mutations relative to HufH18–20/Fc wild-type. The bar graph labeled Control contains no fusion proteins. In all bar graphs, the x axis represents each mutant, and the y axis represents the percentage of binding relative to WT using median fluorescence. Values represent the mean calculated from two or more independently performed experiments ± S.E.