Overlapping Peptide Library Construction


The overlapping peptide library is used to identify the regions in the linear or continuous viral structural proteins that are very important for the activity or are involved in binding with host receptors. It is designed by repeating any number of amino acids with the adjacent peptide. ALL Chemistry is a professional supplier that provides customizable, fully synthetic peptide libraries for mid- to high-throughput applications. As an important tool for peptide sequence optimization important tool for peptide sequence optimization, functional overlapping peptide library is recommended for studying the fuction of the required library.


Introduction of Overlapping Peptide Library

The Overlapping Peptide Library allows you to generate overlapping peptides to cover the full length of the protein of interest. You can define sequence parameters, such as the length of the peptide segment and the number of amino acid offsets. The designed sequence can be edited and exported to Word or Excel format. The design of an overlapping peptide library is mainly determined by the two parameters of peptide chain length and offset number. The design is gradually intercepted from the N-terminus of the target protein to the C-terminus. Each time one or a few amino acids are transferred, there is a partial overlap between the sequences. Finally, an overlapping peptide library is formed. 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. The 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.

Production method: By artificially synthesizing genes encoding random polypeptide segments and then cloning these genes into phage vectors, using phage epitope display technology to display the polypeptides one by one on the surface of the phage to construct a polypeptide library, Many peptide libraries are produced on solid supports such as resins or beads, and they can also be packed in vials or test tubes. Based on the specific interactions between biological macromolecules, small molecules that can mimic the biological functions and activities of specific biological macromolecules can be screened from the library through specific immune responses similar to antigens and antibodies. Careful selection of the offset number and the peptide length can minimize experiment costs while maximizing data value. The offset number is usually designed to be 1/3 of the peptide length. The combination of a low offset number and a short peptide length generates the largest number of peptides, while the combination of a high offset number and a long peptide length produces the least number of peptides.


Fig.1 Epitope


Application of Overlapping Peptide Library


--Scan an Antigen Sequence for Epitopes: Epitopes are specific regions on antigens that are recognized by antibodies or T-cells. The Overlapping Peptide Library enables researchers to scan an antigen sequence systematically, breaking it down into overlapping fragments. By synthesizing and testing these peptides individually, scientists can identify the precise epitopes that elicit an immune response. This knowledge is crucial for designing vaccines, understanding disease mechanisms, and developing targeted therapies.

--Screen a Protein for a Substrate: Proteins often interact with other molecules, such as enzymes with substrates. The Overlapping Peptide Library can be employed to screen a protein for potential substrates. By generating a library of overlapping peptides derived from the protein of interest, researchers can assess the binding affinity and specificity of each peptide towards potential substrates. This screening process aids in unraveling the complex network of protein-protein interactions and provides insights into cellular signaling pathways.

--Identify a T-cell Epitope: T-cells play a vital role in immune responses by recognizing and eliminating infected or abnormal cells. The Overlapping Peptide Library is particularly useful in identifying T-cell epitopes, which are critical for developing vaccines and immunotherapies. By exposing T-cells to a library of overlapping peptides derived from a specific protein, researchers can determine which peptides stimulate T-cell activation. This information aids in understanding immune responses, autoimmune diseases, and designing personalized immunotherapies.

--Stimulate T-cells in T-cell Assays: In addition to identifying T-cell epitopes, the Overlapping Peptide Library can be used to stimulate T-cells in various T-cell assays. By exposing T-cells to a library of overlapping peptides, researchers can measure cytokine production, proliferation, and cytotoxicity, providing valuable insights into T-cell functionality. These assays are crucial for studying immune responses, vaccine development, and assessing the efficacy of immunotherapies.

--Map Antibody Epitopes: Antibodies play a crucial role in immune defense by recognizing and neutralizing pathogens. The Overlapping Peptide Library facilitates the mapping of antibody epitopes, enabling researchers to identify the specific regions on antigens that antibodies bind to. This information is vital for understanding antibody-antigen interactions, developing diagnostic tests, and designing therapeutic antibodies.

--Search for Other Binding Sites Within a Given Protein: Proteins often possess multiple binding sites, enabling them to interact with various molecules simultaneously. The Overlapping Peptide Library can be employed to search for additional binding sites within a given protein. By systematically testing overlapping peptides derived from the protein sequence, researchers can identify novel binding sites, uncovering new functional roles and potential therapeutic targets.


Fig.2 Schematic presentation of constructing the CX7C-peptide library in phage and the principle of in vivo phage display.


Overlapping Peptide Library Services at ALL Chemistry


Overlapping peptide libraries can be used for epitope mapping, which can be used to determine essential regions of a protein or peptide contributing to bioactivity. The library is designed based on two parameters: Peptide fragment length and offset number. The peptide fragment length is the length of each peptide generated in the library and is typically between 10 and 25 amino acids in length. The offset number is the degree of overlap with the following peptide fragment. Overlapping peptide libraries are ideal for T-cell epitope searching because T-cell epitopes are by nature short linear peptides from the primary protein sequence. They are also appropriate for scanning the primary sequence of proteins for B-cell (antibody-defined) epitopes. ALL Chemistry has set up a series of standards to provide a stable platform for the construction of the overlapping library.


Advantages of Our Services


ALL Chemistry guarantees that the purity of the crude peptide library is > 30%. The purity of the crude product can also be as high as 80%, which mainly depends on the characteristics of the polypeptide sequence itself.

Pure peptide library, according to customer needs, we can provide different levels of purity: > 70%, > 80, or even 98%.

The length of each polypeptide is 5-20aa.

Polypeptide modification includes fluorescence labeling, biotin labeling and D- amino acids.

The minimum starting quantity of polypeptide library is 48 peptides.

The general delivery time is 2-3 weeks. The peptide library was directly freeze-dried in a 96-well plate, which can be directly used in subsequent experiments.

Strict Quality Control: Each polypeptide product is provided with MS and HPLC identification results.


Project Workflow


Evaluation → Experiment Design → Formal Quotation → Overlapping Peptide Library Construction → Results → Delivery