Effects of oligopeptide's conformational changes on its adsorption

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Peptide Chemistry

Background:

• Peptide adsorption onto materials is crucial for applications like drug delivery and biosensing.
• Understanding how adsorbent properties influence peptide conformation and binding is key to optimizing these applications.

Purpose of the Study:

• To investigate the effect of cross-linked polymer adsorbents with varying functional groups on the adsorption and conformational changes of the oligopeptide VW-8.
• To determine the adsorption capacity and binding affinity of different adsorbents for VW-8.

Main Methods:

• Preparation of cross-linked polymer adsorbents: APhe (phenylalanine), ALeu (leucine), and AAsp (aspartic acid).
• Adsorption experiments to determine VW-8 capacity.
• Analysis of VW-8 adsorption using Surface Plasmon Resonance (SPR), Nuclear Magnetic Resonance (NMR) spectroscopy, and Isothermal Titration Calorimetry (ITC).

Main Results:

• APhe exhibited the highest VW-8 adsorption capacity (13.6 mg/g) and affinity (K(a)=2.59×10(7) M(-1)).
• APhe induced a conformational change in VW-8 from a random-coil to a β-strand structure, attributed to strong ring stacking and electrostatic interactions.
• ALeu showed lower adsorption capacity and affinity (K(a)=6.23×10(5) M(-1)) with hydrophobic interactions insufficient to induce regular conformational changes.
• AAsp demonstrated lower capacity compared to APhe and ALeu.

Conclusions:

• The conformational changes of peptides during adsorption are significantly influenced by the chemical properties of the adsorbent.
• Adsorbents like APhe, which provide strong non-covalent interactions (ring stacking, electrostatic), can effectively induce specific peptide conformations, leading to higher adsorption affinity.
• This study demonstrates a strategy for designing adsorbents to control peptide adsorption through induced conformational changes.