Voltage Dependent Structure ​ of Ion Transport Channels in Membranes​

February 23, 2020
Voltage Dependent Structure ​ of Ion Transport Channels in Membranes​
A cyclic sequence of voltage pulses (shown with top and bottom electrodes), synchronized with neutron pulses of 30 Hz were applied to a voltage-gated potassium ion channel ensemble embedded in a phospholipid bilayer membrane (shown between the electrodes) yielding in-situ neutron reflectometry profiles (upper right).​

Scientific Achievement

The structure of a voltage gated potassium channel in a phospholipid bilayer membrane was determined for activated (open) and deactivated (closed) states of the channel.​

Significance and Impact

Voltage-gated cation channels are central to neurological signal transmission. Experimental results aid in their understanding by confirming one computational model and ruling out two competing ones.

Research Details

  • In a specially developed neutron reflectometry cell, an alternating voltage with a frequency of 60 Hz to 20 Hz was applied to a thin membrane layer. ​
  • The alternating voltage was synchronized with each neutron pulse, enabling the determination of the reflectometry profiles for different activation states of the potassium channels through the membrane.​

“Voltage-Dependent Profile Structures of a Kv- Channel via Time-Resolved Neutron Interferometry”​
Andrey Y. Tronin, Lina J. Maciunas, Kimberly C. Grasty, Patrick J. Loll, Haile A. Ambaye, Andre A. Parizzi, Valeria Lauter, Andrew D. Geragotelis, J. Alfredo Freites, Douglas J. Tobias, and J. Kent Blasie, Biophysical Journal, 117, 4, , 751-766 (2019). ​
DOI: https://doi.org/10.1016/j.bpj.2019.07.011