Investigating how biological pores open and close

Ion channels are protein molecules that form tiny pores in the cell membrane through which ions (e.g., K+, Ca2+, Na+ or Cl-) can flow. Ligand-gated ion channels play key roles in neuronal excitability and sensory signalling. The opening and closing behaviour of these channels is regulated by the binding of small “second-messenger” molecules to a particular part of the ion channel. In cooperation with colleagues from Heinrich-Heine-Universität Düsseldorf and the Center of Advanced European Studies and Research in Bonn, Professor Dieter Willbold and Dr. Sven Schünke from the Forschungszentrum Jülich have now gained new insights into how the second-messenger molecule can open the ligand-gated ion channel. The scientists solved the structure of a certain part of the ion channel in atomic resolution using high-field nuclear magnetic resonance spectroscopy. Furthermore, they were able to show that the binding of the second-messenger cAMP molecule leads to major conformational changes in the protein structure and opens the channel.

The scientists used a bacterial ion channel as a model system that closely resembles channels in heart muscle cells. “What we have here is a wonderful example of the close interplay between structural biology as a key technology and the field of health research,” says Willbold. A deeper understanding of the molecular processes occurring in ion channels could facilitate the rational development of drugs.

Forschungszentrum Jülich/red.