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Updated: May 25, 2026
07:31
Realistic Membrane Modeling Using Complex Lipid Mixtures in Simulation Studies
Published on: September 1, 2023
Zwitterionic lipid (DPPC)-protein (BSA) complexes at the air-water interface
Sarathi Kundu1, H Matsuoka, H Seto
1Physical Sciences Division, Institute of Advanced Study in Science and Technology, Garchuk, Guwahati, Assam, India. sarathi.kundu@gmail.com
Colloids and Surfaces. B, Biointerfaces
|February 4, 2012
Summary
This study shows that bovine serum albumin (BSA) can form complexes with dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid layers. Complexation occurs across a wide pH range, even beyond BSA's isoelectric point.
Area of Science:
- Biophysics
- Surface Chemistry
- Protein-Lipid Interactions
Background:
- Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) is a zwitterionic lipid.
- Bovine serum albumin (BSA) is a model protein with an isoelectric point near pH 4.8.
- Protein-lipid interactions are crucial in biological systems.
Purpose of the Study:
- To investigate the complexation of DPPC and BSA at the air-water interface.
- To determine the influence of pH and divalent cations on complex formation.
- To elucidate the structural arrangement of BSA-DPPC complexes.
Main Methods:
- Surface pressure (π) - mean molecular area (A) isotherms.
- X-ray reflectivity measurements.
- Controlled air-water interface experiments across a pH range (4.0-9.0) with Ca(2+).
Main Results:
- Complexation between BSA and DPPC occurs across a broad pH range, both below and above BSA's isoelectric point.
- Analysis of isotherms and X-ray reflectivity confirms interaction and complex formation.
- A single layer of BSA was consistently observed to form below the DPPC lipid monolayer.
Conclusions:
- BSA can complex with DPPC lipid monolayers irrespective of pH relative to its isoelectric point.
- The presence of Ca(2+) facilitates BSA-DPPC complexation at the air-water interface.
- The findings provide insights into protein-lipid interactions and complex assembly.
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