In an Overlapping Library, a peptide overlap is defined by the two parameters, “length” and “offset number”, which together describe the degree of overlap.

It is typically used for linear or continuous epitope mapping to understand which part of a peptide or protein contains the critical amino acids that relate to their respective functionality.

In an Alanine Scan, each amino acid in the peptide is sequentially substituted with Alanine (as it is the smallest chiral amino acid), to determine the importance of that amino acid residue in the peptide activity. A substantial reduction in peptide activity upon substitution(s) would indicate the critical amino acid(s) for the function of that peptide.

It is typically used to identify amino acid residues responsible for the peptide activity.

In a Truncation Library, each anking amino acid residue is systematically removed from the original peptide until the shortest sequence required for the activity of the peptide is achieved.

This is typically done after an Alanine Scan where once the critical amino acid residues are identified, the Truncation Library can be used to test the role of the amino acid residues on anking regions of these critical amino acid residues.

A Truncation Library is used to determine the minimum length of a peptide required for epitope activity.

The T-cell Truncated Library consists of pools of sequentially truncated peptide combinations, usually ranging from 11 to 8-mers. After screening, once a positive pool has been identified, the pool can be deconvoluted to identify the precise epitope sequence.

This methodology allows testing of all possible T-cell epitopes across a protein of interest.

In a Positional Scan, the amino acid of interest at a given position(s) is individually substituted with every other amino acid residue at that position to measure the change in activity. The highest activity measured upon replacement of an amino acid residue at the selected position would indicate the preferred amino acid residue(s) for that position.

It is typically used for peptide sequence optimization.

A Scrambled Library is generated through sequence permutation of the original peptide sequence.

It is typically used to either search for new active peptides via generation of a random screening library, or as a negative control to show that a specific sequence of an amino acid is critical for the peptide activity.