| AVS 62nd International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeM |
| Session: | Biomolecules at Interfaces |
| Presenter: | Philipp Stock, Max-Planck Institut für Eisenforschung GmbH, Germany |
| Authors: | P. Stock, Max-Planck Institut für Eisenforschung GmbH, Germany T. Utzig, Max-Planck Institut für Eisenforschung GmbH, Germany M. Valtiner, Max-Planck Institut für Eisenforschung GmbH, Germany |
| Correspondent: | Click to Email |
Placing hydrophobes into an aqueous medium gives rise to what is well known as so-called hydrobobic interaction (HI) or hydrophobic force. This thermodynamic driven force gives rise to interaction and/or self-organisation of solvated hydrophobes in water. Famous examples are protein folding, lipid-bilayer membrane stability and enzymatic catalysis.
Here we will describe a SM-AFM setup to measure the interaction free energies (ΔG0) of eight different hydrophobic peptides interacting with extended hydrophobic surfaces. First, we estimate the free energy of a single hydrophobic unit interacting with an extended hydrophobic surface. Secondly, we measured the change in free energy upon increasing the number of hydrophobic units in different sequences (synergies vs antagonistic effects).
In particular, we studied the change in free energy by placing a spacer groups (glycine) between the hydrophobic units. Interestingly our data shows that the interaction free energy scales with the number of hydrophobic units. Each hydrophobic unit seems to contribute about 4.8 kT. As such we observe a good agreement with values measured for two interacting benzene molecules in water.
Hence, hydrophobic interaction energies of hydrophobic surfaces with hydrophobic peptide fragments on a flexible peptide chain seem to linearly add up, irrespective of the incorporation sequences.