Fellows Seminar - Nanoarchitectonics for the spectroscopic study of the reaction mechanism of proteins

By Petra Hellwig, 2018 Fellow

Membrane proteins are essential to crucial processes such as membrane transport, signaling, respiration and photosynthesis. It is estimated that, in the next century, 80 to 90% of ‘druggable’ targets are membrane proteins. Their contributions to the energy state of the cell are ruled by their conformation and position, as well as the reactivity of specific residues, in response to the electrochemical ion gradients that are composed of an electrical and a concentration component. A common motif in proton translocating membrane proteins consists of several well-defined acid/base pair(s) with specifically shifted pK values, a topic  that is increasingly at the focus of current frontier research.

By combining infrared spectroscopies and solid-state plasmonic nanostructures with an excitation at wavelengths that are specific for the signature of protonated acidic residues, protein backbone and the overall hydrogen-bonding network in the protein, the reactions of the protein during reaction can be visualized. In addition to a label-free detection of the protein’s reaction, the use of -SCN groups as small versatile IR labels is possible.

The perspectives relating to the use of nanoarchitectures for infrared spectroscopies on large molecular ensembles, and for the development of experimental cells that work with sample concentrations in the picomolar range, will be discussed.

• More information on Petra Hellwig and her USIAS project: The reaction mechanism of proteins studied in nanopores.