Proteinstruktur med atomsond

Research Project, 2017 – 2020

In the proposed research a new technique, Atom Probe Tomography Proteomics (APTP), will be developed that has the potential to reveal the native 3D structure of proteins, with near atomic resolution, in complex environments such as cell membranes.

The novelty of the project is to use silica as water replacement for specimen preparation for atom probe tomography. APTP specimens containing proteins of choice in their natural state will be prepared. Such protein immobilization strategy has been shown to retain both protein structure and function; however, this is the first time that it is used together with APT, which insures the originality and novelty of the scientific idea. The silica is formed in a polymerization process slowly replacing water with silica resulting in a solid silica piece. As the reaction is possible to achieve at low temperature and at near physiological pH, it is suitable for protein embedding, which has been clearly demonstrated. The obtained protein embedded silica pieces are then sculptured using focused ion beam (FIB), followed by a tip-sharpening step that produces atom probe needles, which are about 20-100 nm in width. The needles are then placed in the atom probe where an electric field combined with a laser are used to “peel off” ions. These are then detected by a position sensitive mass spectrometer (ToF-detector) and later 3D reconstructed using software.