Enhancing the affinity of SEB-binding peptides by repeating their sequence.

Area of Science:

• Biochemistry and Molecular Biology
• Biotechnology
• Analytical Chemistry

Background:

• High-affinity peptide ligands are crucial for effective biosensors and bioassays.
• Previous work identified 12-mer peptides that selectively bind Staphylococcal enterotoxin B (SEB) via phage display.
• Enhancing the affinity of these SEB-binding peptides is key for improved detection capabilities.

Purpose of the Study:

• To explore novel modification strategies for increasing the affinity of two identified SEB-binding peptides.
• To investigate the structural basis for affinity changes in modified peptides.
• To develop a high-affinity molecular recognition agent for SEB detection in biosensing systems.

Main Methods:

• Alanine scanning mutagenesis was performed to identify critical residues and binding regions.
• Peptide sequences were modified by repeating the 12-mer motif (dimers and trimers).
• Binding affinity was assessed, and structural insights were gained using molecular dynamics simulations.

Main Results:

• Alanine substitution mutants completely lost SEB binding affinity, preventing identification of specific binding regions.
• Repeating the 12-mer peptide sequence resulted in a 10-fold increase in binding affinity for one peptide.
• Further triplication of the enhanced peptide sequence led to decreased affinity, suggesting an optimal repeat number.

Conclusions:

• Peptide sequence repetition is an effective strategy for enhancing binding affinity to SEB.
• Conformational changes induced by sequence repetition are critical for modulating peptide affinity.
• The developed high-affinity peptide is a promising candidate for SEB detection in advanced biosensing applications.