A positional scanning library is an important tool for peptide sequence optimization. Amino acids of interest at a given position(s), are substituted with all other natural amino acids, one at a time. This allows for amino acids that enhance peptide activity to be identified.

In particular, positional scanning libraries have been used to identify T-cell epitopes from complex mixtures of proteins. In addition, this type of library can also be used to locate substrates with interdependent subsites with only minimum synthesis and screening.

Applications of Positional Scanning Library

Optimize peptide binding sites

Increase activity of enzyme substrates

Enhance antibody epitopes

Improve T-cell epitopes

Overlapping Peptide
Alanine Scanning
Truncation Library
Positional Scanning
Random Library
Scrambled Library
T Cell Truncated Library


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  • Lee CH, Lee MS, Kim SJ, Je YT, Ryu SH, and Lee T. Identification of novel synthetic peptide showing angiogenic activity in human endothelial cells. Peptides. Oct 2008 17.
  • Chaparro RJ, Burton AR, Serreze DV, Vignali DA, and DiLorenzo TP. Rapid identification of MHC class I-restricted antigens relevant to autoimmune diabetes using retrogenic T cells. J. Immunol. Methods. Jun 2008 1; 335(1-2): 106-15.
  • Nino-Vasquez JJ, Allicotti G, Borras E, Wilson DB, Valmori D, Simon R, Martin R, and Pinilla C. A powerful combination: the use of positional scanning libraries and biometrical analysis to identify cross-reactive T cell epitopes. Mol. Immunol. Feb 2004; 40(14-15): 1063-74.
  • Houghten RA. The broad utility of soluble peptide libraries for drug discovery. Gene. Dec 1993 27; 137(1): 7-11.


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