Abstract
Continuum elastic models that account for membrane thickness variations are especially useful in the description of nanoscale deformations due to the presence of membrane proteins with hydrophobic mismatch. We show that terms involving the gradient and the Laplacian of the area per lipid are significant and must be retained in the effective Hamiltonian of the membrane. We reanalyze recent numerical data, as well as experimental data on gramicidin channels, in light of our model. This analysis yields consistent results for the term stemming from the gradient of the area per molecule. The order of magnitude we find for the associated amplitude, namely 13–60 mN/m, is in good agreement with the 25 mN/m contribution of the interfacial tension between water and the hydrophobic part of the membrane. The presence of this term explains a systematic variation in previously published numerical data.
Highlights
As basic constituents of cell membranes, lipid bilayers [1] play an important role in biological processes, not as a passive background, but rather as a medium that responds to and influences, albeit in a subtle way, the behavior of other membrane components, such as membrane proteins [2]
Since the range of such deformations is of the same order as membrane thickness, one can wonder to what extent continuum elastic models in general still apply, and what level of complexity is required for an accurate description
We show that these new terms cannot be neglected, as they contribute to important terms in the bilayer effective Hamiltonian
Summary
As basic constituents of cell membranes, lipid bilayers [1] play an important role in biological processes, not as a passive background, but rather as a medium that responds to and influences, albeit in a subtle way, the behavior of other membrane components, such as membrane proteins [2]. At length scales much larger than their thickness, the elasticity of lipid bilayers is well described by the Helfrich model [3]. Some transmembrane proteins have a hydrophobic part with a thickness slightly different from that of the hydrophobic part of the membrane Due to this hydrophobic mismatch, the hydrophobic core of the membrane locally deforms [4,5,6]. As this deformation affects the thickness of the membrane, and as its characteristic amplitude and decay length are both of a few nanometers [7], it cannot be described using the Helfrich model. Which terms must be retained in a deformation expansion of the effective Hamiltonian?
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
