Protein-induced bilayer perturbations: Lipid ordering and hydrophobic coupling

Journal Article · Fri Oct 02 04:00:00 EDT 2009 · Biochemical and Biophysical Research Communications

DOI:https://doi.org/10.1016/J.BBRC.2009.07.109· OSTI ID:22199817

Petersen, Frederic N.R.; Laursen, Ib; Bohr, Henrik ^[1]

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1. Quantum Protein Center, Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

The host lipid bilayer is increasingly being recognized as an important non-specific regulator of membrane protein function. Despite considerable progress the interplay between hydrophobic coupling and lipid ordering is still elusive. We use electron spin resonance (ESR) to study the interaction between the model protein gramicidin and lipid bilayers of varying thickness. The free energy of the interaction is up to -6 kJ/mol; thus not strongly favored over lipid-lipid interactions. Incorporation of gramicidin results in increased order parameters with increased protein concentration and hydrophobic mismatch. Our findings also show that at high protein:lipid ratios the lipids are motionally restricted but not completely immobilized. Both exchange on and off rate values for the lipid {r_reversible} gramicidin interaction are lowest at optimal hydrophobic matching. Hydrophobic mismatch of few A results in up to 10-fold increased exchange rates as compared to the 'optimal' match situation pointing to the regulatory role of hydrophobic coupling in lipid-protein interactions.

• OSTI ID: 22199817
• Journal Information: Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 4 Vol. 387; ISSN BBRCA9; ISSN 0006-291X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CONCENTRATION RATIO
COUPLING
ELECTRON SPIN RESONANCE
FREE ENERGY
LIPIDS
MEMBRANE PROTEINS
ORDER PARAMETERS
PERTURBATION THEORY