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High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Reorientational and conformational ordering processes at elevated pressures in 1,2-dioleoyl phosphatidylcholine: a
Biophysical Journal
|May 12, 2009
Summary
High hydrostatic pressure transforms 1,2-dioleoyl phosphatidylcholine (DOPC) bilayers into a highly ordered gel state. This transition reveals unique molecular packing and conformational changes in the lipid
Area of Science:
- Biophysics
- Lipid Bilayer Research
- Materials Science
Background:
- 1,2-dioleoyl phosphatidylcholine (DOPC) is a common phospholipid in cell membranes.
- Under normal conditions, DOPC exists in a fluid liquid crystalline state.
- Understanding lipid behavior under pressure is crucial for biological and material applications.
Purpose of the Study:
- To investigate the structural and dynamic changes in hydrated DOPC bilayers under high hydrostatic pressure.
- To characterize the phase transition from liquid crystalline to gel state induced by pressure.
- To elucidate the molecular mechanisms behind the pressure-induced ordering.
Main Methods:
- Raman spectroscopy
- Infrared spectroscopy
- Variable hydrostatic pressure application (up to 37 kbar)
Main Results:
- A first-order phase transition from liquid crystalline to gel state was observed at 5 kbar.
- In the gel phase, DOPC molecules exhibit extended methylene chains and bent oleoyl chains due to cis double bonds.
- Unique parallel packing of bent oleoyl chains was observed, facilitated by glycerol head group rotations.
- Olefinic CH bonds rotate out of plane, and opposing bilayer chains bend in opposite directions.
Conclusions:
- Hydrostatic pressure induces significant conformational and dynamic ordering in DOPC bilayers.
- The pressure-induced gel phase of DOPC displays unique interchain interactions and molecular arrangements.
- These findings provide insights into lipid behavior under extreme conditions and potential applications.
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