Evaluation of peptide-peptide interactions using reversed-phase high-performance liquid chromatography

Area of Science:

• Biochemistry
• Analytical Chemistry
• Structural Biology

Background:

• Reversed-phase high-performance liquid chromatography (RP-HPLC) separates peptides based on hydrophobic interactions with C18 stationary phases.
• Understanding peptide behavior in RP-HPLC is crucial for analyzing complex peptide mixtures and protein structures.

Purpose of the Study:

• To investigate self-induced conformational effects in dimeric disulfide-linked model peptides during RP-HPLC.
• To correlate peptide structure and intermolecular interactions with chromatographic retention behavior.

Main Methods:

• Synthesis of 18 analogues of an amphipathic alpha-helical peptide sequence, with sequential cysteine substitutions.
• Analysis of dimeric peptide behavior using RP-HPLC.
• Circular dichroism spectroscopy to determine secondary structure in aqueous solutions.

Main Results:

• Dimeric peptides exhibited strong interchain hydrophobic interactions, leading to preferential presentation of lysine residues to the C18 stationary phase.
• These interactions resulted in significantly earlier retention times in RP-HPLC.
• Three homo-dimers demonstrated stable, strong alpha-helical conformations in water, confirmed by circular dichroism.

Conclusions:

• Peptide conformation and strong intermolecular hydrophobic forces significantly impact RP-HPLC retention times.
• Self-induced conformational effects in dimeric peptides can alter their interaction with the stationary phase, affecting separation.
• The study highlights the importance of considering peptide structure and interactions for accurate RP-HPLC analysis.