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High-throughput Crystallization of Membrane Proteins Using the Lipidic Bicelle Method
Published on: January 9, 2012
Induced helical conformation of ionic polypeptides by phospholipids solubilized in a nonionic surfactant solution
International Journal of Peptide and Protein Research
|March 1, 1979
Summary
Phospholipids like phosphatidylcholine and phosphatidylserine, when solubilized with a nonionic surfactant, induce helical structures in poly (L-glutamic acid) and poly (L-lysine) respectively. The surfactant stabilizes these phospholipid-polypeptide complexes without altering polypeptide conformation.
Area of Science:
- Biochemistry
- Polymer Science
- Surfactant Chemistry
Background:
- Phospholipids are key components of cell membranes.
- Polypeptides can adopt various conformations, including helical structures.
- Nonionic surfactants are used to solubilize and stabilize biological molecules.
Purpose of the Study:
- To investigate the conformational changes of polypeptides induced by solubilized phospholipids.
- To explore the formation and stability of phospholipid-surfactant mixed micelles.
- To determine the role of nonionic surfactants in phospholipid-mediated polypeptide transformations.
Main Methods:
- Solubilization of phospholipids (phosphatidylcholine, phosphatidylserine) using hexadecylpoly (oxyethylene) ether.
- Observation of polypeptide (poly (L-glutamic acid), poly (L-lysine)) conformation using techniques sensitive to secondary structure.
- Characterization of mixed micelle formation and stability.
Main Results:
- Solubilized phosphatidylcholine induced a coil-to-helix transformation in poly (L-glutamic acid) at neutral pH.
- Solubilized phosphatidylserine promoted a helical conformation in poly (L-lysine) at neutral pH via complex formation.
- The mixed micelles formed were thermodynamically stable.
- The nonionic surfactant did not affect the inherent conformation of the polypeptides.
Conclusions:
- Phospholipids, when appropriately solubilized, can act as agents to induce specific secondary structures in polypeptides.
- Stable phospholipid-surfactant complexes can be formed, facilitating interactions with polypeptides.
- This study highlights a mechanism for controlling polypeptide conformation through lipid-surfactant systems.
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