Selection of peptides that bind to the core oligosaccharide of R-form LPS from a phage-displayed heptapeptide library

To characterize common sites within the core oligosaccharide of the R-form lipopolysaccharide (LPS), we screened peptides from a phage-displayed heptapeptide library by using the most truncated form of R-LPS, Re-LPS (S. Typhimurium SL1165) as a ligand. After three rounds of biopanning/amplification and subsequent screening by phagemid enzyme-linked immunosorbent assay (ELISA), we selected three distinct clones that bind to the ligand LPS. We characterized the binding sites of the three clones by ELISA and thin-layer chromatography immunostaining and found that the three clones bind the two Re-LPSs (SL1165 and S. Minnesota Re595) and Rb2-LPS. In addition, one of the clones also bound to S-form LPS (S. Enteritidis). Current data show that those clones bind to common carbohydrate structure(s) expressed in the core oligosaccharides of those LPS samples.