Fig. 3.

Fine specificity described by exhaustive single substitution scans. Single substituted analog peptides, scanned through all 15 positions of the native peptide sequence and including all 20 naturally occurring amino acids, were synthesized and tested for binding to the appropriate anti-PrEST antibody. The relative signals of the analog peptide and of the native peptide are shown and color shaded so that reddish hues are assigned to substitutions resulting in reduced binding of the antibody. A, Position specific scoring matrix (PSSM) representing RS values of a single substitution scan of the 15-mer peptide RAEVTEEFKDPSDRV. B, The EF-DPS epitope identified from the RAEVTEEFKDPSDRV peptide. C, PSSM representing RS values of single substitution scans of the 15-mer peptide AVMKLITSDVLEEML. The PSSM matrices were also visualized as sequence logos using the Sequence2Logo server (http://www.cbs.dtu.dk/biotools/Seq2Logo-1.0/). D, The KLITSDV epitope identified from the AVMKLITSDVLEEML peptide.