Cells need openings in the cell membrane in order to make exchanges with their environment. These openings are closable portals in which the signals are transported in the form of ions. Private lecturer Dr. Indra Schröder from the Department of Membrane Biophysics at the TU Darmstadt, which is run by Professor Gerhard Thiel, is interested in potassium channels. The physicist and head of the junior research group has her very own view of these tiny molecular machines. She is not so much interested in the biological signals that are exchanged via the channels, but in the biophysical closing mechanism. Schröder wants to know what the molecular bolt looks like and how it works.
To that end, the physicist works with very basic potassium channels so as not to make the analysis unnecessarily complicated. She uses two systems with a similar structure but different opening probabilities. One channel is almost always closed, the other almost always open. Both channels originated from algae viruses, but strongly resemble the potassium channels of higher organisms. Schröder works in a cell-free system, and fits the potassium channels into artificial surfaces. “We concentrate solely and exclusively on the closing mechanism, and blend out all the other functions of the potassium channels,” says Schröder. “This is legitimate, because the potassium channels are all similar to each other. We are basically working on a prototype, what you could call a model potassium channel.”
Amino acid serine at a critical point
Schröder and her doctoral student Oliver Rauh have mutated both potassium channels and pushed individual parts…