Overlapping Peptide Library
An overlapping peptide library can be used for linear or continuous epitope mapping, which can be used to figure out which part of a given protein or peptide contains the essential amino acids that contribute to its functionality. Characterized by two parameters, peptide length and offset number, each library is generated by dividing the original protein or peptide into many overlapping peptides of equal length. Optimum peptide length is 8 to 20 amino acids, and as a general guideline, a peptide must be at least six residues in length for it to cover an epitope. The offset number is the number of amino acid residues shared by adjacent peptides, and it reflects the degree of overlap.
Careful selection of the offset number and the peptide length can minimize experiment cost, while maximizing data value. The offset number is usually designed to be 1/3 of the peptide length. Long peptides will generate more epitope hits per peptide, but they are difficult to synthesize and the library will contain fewer peptides. Shorter peptides are easier and cheaper to synthesize, but will result in fewer epitope hits per peptide. The combination of low offset number and short peptide length generates the largest number of peptides, while the combination of high offset number and long peptide length produces the least number of peptides.
Applications Of Overlapping Library
- Scan an antigen sequence for epitopes
- Screen a protein for a substrate
- Identify a T-cell epitope
- Stimulate T-cells in T-cell assays
- Map antibody epitopes
- Search for other binding sites within a given protein
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- Hemmer B, Pinilla C, Appel J, Pascal J, Houghten R, and Martin R. The use of soluble synthetic peptide combinatorial libraries to determine antigen recognition of T cells. J. Pept. Res. Nov 1998; 52(5): 338-45
- Sung MH, Zhao Y, Martin R, and Simon R. T-cell epitope prediction with combinatorial peptide libraries. J. Comput. Biol. 2002; 9(3): 527-39
- Paulmurugan R, and Gambhir SS. Combinatorial library screening for developing an improved split-firefly luciferase fragment-assisted complementation system for studying protein-protein interactions. Anal. Chem. Mar 2007; 15; 79(6): 2346-53