Insights into the molecular mechanism of gating of eukaryotic cyclic nucleotide-modulated ion channels using structural and functional tools

• Applicant: Dr. Philipp Schmidpeter
• Subject Area: Biochemistry
• Term: from 2015 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 271275232

Cyclic nucleotide (cN) modulated ion channels such as cN gated (CNG), and hyperpolarization activated and cN gated (HCN) ion channels play important roles in olfactory and visual signaling cascades as well as the pacemaker activity in the heart and brain. They are members of the S4-containing voltage gated ion channel family with an additional cytoplasmic cN binding domain attached to the pore via a helical bundle called theC-linker. To date there is no high-resolution structure of the full-length channel and no functional characterization of the purified channel protein.Our aim is to contribute to the understanding how ligand binding leads to pore gating in CNG/HCN channels by characterizing the structure and function of purified channels in a defined membrane environment. Bacteria, in vitro translation, yeast, and insect cells will be employed to optimize the expression of these channels. For functional assays, the purified channels will be transfer to liposomes or nanodiscs to improve protein stability. We will characterize the purified channels using electrophysiology techniques. The energetics of cN binding to purified CNG/HCN full-length channels and structural data will complement the functional and biophysical characterization. This will enhance our understanding of how these channels gate at the molecular level.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Crina Nimigean, Ph.D.