Fig. 5: The GET insertase distorts the lipid bilayer.
From: The GET insertase exhibits conformational plasticity and induces membrane thinning
A Model for nanodisc-embedded ctGet2ΔN-Get1/Get3 superimposed with the cryo-EM density contoured to 0.092. The dashed cylinder shows the trajectory of the unresolved N-terminal portion of ctGet2 TMD3. The approximate thickness of the nanodisc membrane at different positions is indicated. B, C Membrane behaviour as captured in atomistic MD simulations of hsGet1/Get2 embedded in a 20/80 (mol%/mol%) 16:0-18:1 phosphatidylinositol (PI)/16:0-18:1 phosphatidylcholine (PC) bilayer. B Average 2D membrane thickness map constructed based on the local lipid phosphorus atom distance between upper and lower leaflets. The hsGet1/Get2 TMDs are labelled within the 2D projection. C Average 3D iso-occupancy map for the lipid phosphorus atoms showing local membrane thickness and deformation relative to the structure of hsGet1/Get2. Both 2D membrane thickness maps and the 3D iso-occupancy maps were constructed as an average over all 3 simulation repeats after discarding the first 200 ns from each repeat, after the transmembrane region of the protein is aligned on the membrane plane. The zoomed insets show different views of a representative snapshot of the hydrophilic groove at the end of the third trajectory, with a selection of lipids within the groove displayed in yellow (stick representation for tails, sphere representation for head groups). D Model for hsGet1 superimposed with the hsGet2ΔN/Δα3’-Get1/Get3 cryo-EM density contoured to 0.17. Examples of hydrophilic residues pointing into the groove are shown in red and the unidentified density is in grey. The hydrophilic groove is overlaid with a phospholipid (yellow) from the representative snapshot of the MD simulation shown in (B, C).
