| AVS 66th International Symposium & Exhibition | |
| Biomaterial Interfaces Division | Tuesday Sessions |
| Session BI+AS-TuA |
| Session: | Biomolecules and Biophysics and Interfaces & Flash Session |
| Presenter: | Thaddeus Golbek, Aarhus University, Denmark |
| Authors: | T.W. Golbek, Aarhus University, Denmark H.I. Okur, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland S. Kulik, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland J. Dedic, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland S. Roke, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland T. Weidner, Aarhus University, Denmark |
| Correspondent: | Click to Email |
Highly ordered protein aggregates play a large role in many neurodegenerative and non-neuropathic disorders including type II diabetes, Alzheimer’s, Parkinson’s, prion, and Huntington’s disease. Even though a causative link between the formation of protein aggregates and server diseases has been established, the molecular level-details of protein aggregation and cell membrane disruption are still underdeveloped. One of the most characterized proteins that has been used to model protein aggregation is hen egg-white lysozyme. While lysozyme has been extensively studied at model surfaces, it has not been well studied on curved, more realistic, surfaces. In order to observe lysozyme at a curved surface we applied sum frequency scattering (SFS) vibrational spectroscopy to probe the interface between the protein and the curved lipid model cell membrane surface. The model cell membrane was built upon 10% 1,2-dimyristoyl-sn-glycero-3-phospho-(1’-rac-glycerol) (DMPG) and 90% 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid nanodroplet emulsions, were the oil is n-hexadecane. SFS studies at the protein-lipid interface demonstrate that binding of lysozyme induces increased lipid monolayer order. An increase in acyl chain order determined by the ratio of the CH3 symmetric and CH2 asymmetric peak amplitudes and lipid head group orientation change from about 0˚ to greater than 60˚, determined by the increase is phosphate head group signal, suggests that lysozyme inserts into the lipid layer causing lipid dehydration and reorientation. The amide I SFS spectrum lysozyme interacting with the model cell lipid monolayer is also studied to observe the folding and ordering of the protein. Altogether, we demonstrate the use of lipid monolayer nanodroplet emulsions as a platform to study protein membrane interactions in solution, which excludes air form the model further increasing biomimetic modeling potential using SFS.