The role of charge regulation on the interaction of Histatin 5 with cell membranes
| Reference number | |
| Coordinator | Lunds universitet - Teoretisk kemi |
| Funding from Vinnova | SEK 400 000 |
| Project duration | May 2020 - June 2021 |
| Status | Completed |
| Venture | Research infrastructure - utilisation and collaboration |
| Call | Increasing PhD students' competence in neutron- and synchroton-based analysis methods in industry - spring 2020 |
Important results from the project
The aim of the project was to investigate the importance of charge regulation when antimicrobial peptides, such as the saliva protein Histatin 5, interact with cell membranes using neutron reflectometry measurements. For this purpose, a number of different variants of Histatin 5 were designed with different numbers of histidines. We have used a combination of experiments, such as neutron reflectivity, QCM-D and ellipsometry and computer simulations to understand this.
Expected long term effects
Previous measurements have shown that Histatin 5 is transported through the bilayer and forms a "cushion" and lifts the bilayer from the surface. Our hypothesis was that this "cushion" was dependent on the number of histidines in the primary sequence. In May, July and September 2021, we measured neutron reflectivity on Figaro, D17 and SuperAdam, ILL, Grenoble. The project is ongoing and preliminary analyzes indicate exciting results that we will continue to work on to study objective (ii) and (iii) as well.
Approach and implementation
QCM-D measurements have been performed for all designed variants, both to study the interaction with a bare silicon surface, and with an bilayer with 10% negative charges. In addition to this, ellipsometry measurements have also been made to study the interaction with a bare silicon surface. The secondary structure of all variants has been studied with CD spectroscopy. The data has then been analyzed with BeStSel. Analysis of neutron reflectivity measurements are ongoing.