Fabrication and applications of supercharged, unfolded proteins

PhD ceremony: Ms. A. Kolbe, 14.30 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Fabrication and applications of supercharged, unfolded proteins

Promotor(s): prof. A. Herrmann

Faculty: Mathematics and Natural Sciences

This thesis describes the design and fabrication of supercharged, unfolded proteins (SUPs) based on elastin-like peptides and some of their possible applications.

These charged protein polymers (= protein polyelectrolytes) are less toxic and better defined than commonly used polyelectrolytes and are therefore appealing candidates for applications in biomedicine. Due to electrostatic attraction between oppositely charged SUPs they can be transferred into micro- and nanometer sized objects. To illustrate this, we assembled hollow capsules, which might serve as protective nanocontainers for bioactive compounds, such as drugs or proteins. Furthermore, we showed that we can incorporate a functional protein linked to a SUP variant into the capsule wall. We fabricated capsules containing green fluorecent protein (GFP), which is visible under a fluorescence microscope, and studied the uptake of these capsules by living cells in culture. In the same way, one could think of equipping the capsule wall with a bioactive protein or a targeting protein that directs the capsule with its cargo to a specific cell type that needs to be treated. In another approach, we assessed how the attachment of SUPs with various amounts of charges influences the detection of GFP by charge-sensitive detectors. The detectors we used can sense compounds at very low concentrations and therefore have great potential for detecting heart attacks or cancer at an early stage. Our findings can help to improve the performance of these detectors.