Related Experiment Video
Updated: Apr 7, 2026

Method to Visualize and Analyze Membrane Interacting Proteins by Transmission Electron Microscopy
Published on: March 5, 2017
Lipid insertion domain unfolding regulates protein orientational transition behavior in a lipid bilayer
Kwan Hon Cheng1, Liming Qiu2, Sara Y Cheng3
1Department of Physics, Texas Tech University, Lubbock, TX 79409, USA; Department of Physics and Astronomy, Trinity University, San Antonio, TX 78212, USA.
Abstract:
We have used coarse-grained (CG) and united atom (UA) molecular dynamics simulations to explore the mechanisms of protein orientational transition of a model peptide (Aβ42) in a phosphatidylcholine/cholesterol (PC/CHO) lipid bilayer. We started with an inserted state of Aβ42 containing a folded (I) or unfolded (II) K28-A42 lipid insertion domain (LID), which was stabilized by the K28-snorkeling and A42-anchoring to the PC polar groups in the lipid bilayer. After a UA-to-CG transformation and a 1000ns-CG simulation for enhancing the sampling of protein orientations, we discovered two transitions: I-to-"deep inserted" state with disrupted K28-snorkeling and II-to-"deep surface" state with disrupted A42-anchoring. The new states remained stable after a CG-to-UA transformation and a 200ns-UA simulation relaxation. Significant changes in the cholesterol-binding domain of Aβ42 and protein-induced membrane disruptions were evident after the transitions. We propose that the conformation of the LID regulates protein orientational transitions in the lipid membrane.
Related Concept Videos
Membrane Fluidity
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is...
Membrane Fluidity
Mechanisms of Membrane Domain Formation
Another mechanism for membrane domain formation involves membrane proteins interacting with...
Mechanisms of Membrane-bending
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
Intrinsically Disordered Proteins
Membrane Domains
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the...

