Regulation of channel function due to physical energetic coupling with a lipid bilayer

• Published in: Biochemical and biophysical research communications 2014-03, Vol.445 (2), p.463-468
• Main Authors: Ashrafuzzaman, Md, Tseng, C.-Y., Tuszynski, J.A.
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; CELL MEMBRANES; COMPARATIVE EVALUATIONS; COMPLEXES; COULOMB FIELD; COUPLING; Hydrophobic and Hydrophilic Interactions; Ion channel; ION CHANNELING; Ion Channels - chemistry; Ion Channels - metabolism; LAYERS; Lipid bilayer; Lipid Bilayers - chemistry; Lipid Bilayers - metabolism; LIPIDS; MD simulations; Membrane protein; MEMBRANE PROTEINS; MOLECULAR DYNAMICS METHOD; Molecular Dynamics Simulation; PEPTIDES; Screened Coulomb interaction; Static Electricity; VAN DER WAALS FORCES
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2014.02.012

•Lipid membrane regulation of membrane protein functions has been addressed.•Energetics behind ion channel-membrane coupling phenomena has been investigated.•Charge based interactions stabilize peptide–lipid complex.•Screened Coulomb interaction model explains the energetics.•Van der Waals and electrostatic forces drive peptides and lipids to close proximity. Regulation of membrane protein functions due to hydrophobic coupling with a lipid bilayer has been investigated. An energy formula describing interactions between lipid bilayer and integral ion channels with different structures, which is based on the screened Coulomb interaction approximation, has been developed. Here the interaction energy is represented as being due to charge-based interactions between channel and lipid bilayer. The hydrophobic bilayer thickness channel length mismatch is found to induce channel destabilization exponentially while negative lipid curvature linearly. Experimental parameters related to channel dynamics are consistent with theoretical predictions. To measure comparable energy parameters directly in the system and to elucidate the mechanism at an atomistic level we performed molecular dynamics (MD) simulations of the ion channel forming peptide–lipid complexes. MD simulations indicate that peptides and lipids experience electrostatic and van der Waals interactions for short period of time when found within each other’s proximity. The energies from these two interactions are found to be similar to the energies derived theoretically using the screened Coulomb and the van der Waals interactions between peptides (in ion channel) and lipids (in lipid bilayer) due to mainly their charge properties. The results of in silico MD studies taken together with experimental observable parameters and theoretical energetic predictions suggest that the peptides induce ion channels inside lipid membranes due to peptide–lipid physical interactions. This study provides a new insight helping better understand of the underlying mechanisms of membrane protein functions in cell membrane leading to important biological implications.