The cyclic nucleotide-modulated potassium channel MloK1

  • Two-dimensional crystals of MloK adsorbed to a thin carbon film and imaged by cryo electron microscopy. The largest crystal has a diameter of 5 micrometers.

  • The regular crystal lattice formed by MloK1 in the lipid bi-layer, visible at higher magnification. The large crystal is 1 micrometer long.

  • The crystal lattice at higher magnification, after image processing to enhance contrast and correct imaging aberrations (protein is white). The MloK1 tetramers are 7 nm x 7 nm in size.

  • The colors help to distinguish the 'up'- and 'down'- orientation of the MloK1 in the lipid bilayer. Each tetramer is 7 nm x 7 nm in size.

  • The organization of MloK1 in the lipid bilayer

About-+

Physiologically, cyclic nucleotide-modulated ion channels play a role in signal transduction (e.g., in the olfactory and visual sensory systems) and pacemaking (e.g., in the heart and brain). They couple changes in the levels of intracellular signalling molecules with cellular electrical responses by adjusting the ion flux.

Knowledge of their structure will help guide pharmaceutical research.

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3-D structure of MloK1 determined by 2-D electron crystallography

More detail+-

The goal of our studies is to obtain the structure of the cyclic nucleotide-modulated potassium channel MloK1 in a close-to-native (lipid) environment under different conditions, (e.g., in the absence/presence of an interacting ligand) and, ultimately, at atomic resolution in order to fully understand its function.  

For this, 2-D crystals of the lipid-embedded complex are produced and imaged at high resolution. Various software algorithms developed in-house help to reduce the effect of crystal imperfections, and sample movement and damage during imaging.

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