Positional Peptide Library Construction


Positional scanning peptide library is an important tool for peptide sequence optimization, it was synthesized by systematically substituting one or several fixed residues within a peptide with all other amino acids. ALL Chemistry has the capability to construct any Positional Peptide Library at your request. Our scientists have accumulated extensive experience in different types of Peptide Library Construction.


Introduction of Positional Peptide Library


The Positional Peptide Library is a comprehensive collection of peptide sequences, which is used for sequence updating and modification to enhance polypeptide activity. A selected region or domain of polypeptide is systematically replaced by other amino acids. This peptide library is helpful for scientific researchers to find special regions with unique harm or activity in a special part. Replacing all-natural amino acids at the target site, once for each polypeptide, can be used to identify the polypeptide sequence with the best activity. T cell epitopes are often identified in complex protein mixtures, or substrates are located by interdependent sub-sites to reduce the workload of synthesis and screening. Substitutions can be made at single or multiple positions in a peptide sequence.

These libraries are usually used for the optimization of peptide sequences or as a negative control in experiments. In this library, peptides are systematically substituted for each other. These substitutions help to identify the residues that are most important for the function or activity of that region. One of the examples is the use of positional scanning in a synthetic combinatorial library to identify antivirals against HIV. Boggiano, Reixach, Pinilla, and Blondelle (2003) identified an -helix fusion inhibitor peptide from the gp160 domain of HIV. They designed 18-mer peptides and substituted random l-amino acids in a hydrophilic region at positions 6, 9, 13, and 16. After performing in vitro assays with a series of substituted peptides, they concluded that the inhibitory effects of these peptides were independent of -helix conformation. The peptide library constructed by position scanning is of great reference value to the study of protein interfaces, both in epitope mapping and protein-protein interaction.


Fig.1 Schematic of random peptide library screening process.


Applications of Positional Peptide Library


By varying amino acids at specific positions, Positional Peptide Library plays a huge role in optimizing peptide binding sites, increasing the activity of enzyme substrates, enhancing antibody epitopes, and improving T-cell epitopes.

--Optimize Peptide Binding Sites: Peptide-mediated interactions, in which a short linear motif binds to a globular domain, play major roles in cellular regulation. An accurate structural model of this type of interaction is an excellent starting point for the characterization of the binding specificity of a given peptide-binding domain. Positional Peptide Library enables researchers to fine-tune peptide binding sites by systematically substituting amino acids at specific positions.

--Increase Activity of Enzyme Substrates: Positional Peptide Library plays a crucial role in enhancing the activity of enzyme substrates. By systematically altering amino acids in the peptide sequence, researchers can identify key residues that contribute to enzymatic activity. This knowledge can be utilized to engineer peptides with improved substrate specificity, catalytic efficiency, and stability.

--Enhance Antibody Epitopes: Positional Peptide Library offers a unique platform for optimizing antibody epitopes, which are specific regions on antigens recognized by antibodies. By varying amino acids at specific positions within the epitope, Positional Peptide Library aids in identifying key residues that influence antibody-antigen interactions.

--Improve T-cell Epitopes: Positional Peptide Library also plays a significant role in improving T-cell epitopes, which are recognized by T-cells as part of the immune response. By systematically altering amino acids within the epitope, Positional Peptide Library assists in identifying residues that influence T-cell receptor recognition and activation. This information can be leveraged to design peptides with enhanced immunogenicity, antigen presentation, and T-cell response.



Fig.2 Original Sequence


Positional Peptide Library Services at ALL Chemistry


A positional scanning library is an important tool for peptide sequence optimization. Amino acids of interest at a given position, 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. Scientists at ALL Chemistry continuously strive to produce high-quality Positional Peptide Library Construction and related services to solve problems in scientific discovery.


Advantages of Our Services


Low Cost, Rapidity and Easy Operability.

Accuracy, Visibility and Easy Analysis.

Competitive Prices: Our peptide library services are the most cost-efficient on the market.

Flexible Purity Choices: Crude, desalt, >70%, >75%, >80%, 85%, >90%, >95%, and >98% purity are available to meet your multiple demands.

No Cross-contamination: Peptides are supplied in individual well-labeled vials.

Comprehensive Modifications: Our modification service includes labeling, the incorporation of unnatural amino acids, and peptide cyclization with disulfide bridges.

Stringent Quality Control: ALL Chemistry provides MS and HPLC validation data for each peptide.

Chemistry provides epitope mapping service, binding assay, and functional assay services for your drug discovery research.


Project Workflow


Evaluation → Experiment Design → Formal Quotation → Positional Peptide Library Construction of Peptides → Results → Delivery