Corrections to the Saffman-Delbruck mobility for membrane bound proteins

TL;DR

This paper revises the Saffman-Delbruck model for membrane protein mobility by incorporating membrane deformation effects, explaining experimental deviations and providing a more accurate description of protein diffusion in lipid bilayers.

Contribution

It introduces a correction to the Saffman-Delbruck model accounting for membrane deformation caused by protein-lipid interactions, applicable to various membrane proteins.

Findings

Membrane deformation reduces protein mobility compared to classical predictions.

The correction depends on protein size and deformation characteristics.

Results align with experimental observations by Gambin et al.

Abstract

Recent experiments by Y. Gambin et al. [PNAS 103, 2098 (2006)] have called into question the applicability of the Saffman-Delbruck diffusivity for proteins embedded in the lipid bilayers. We present a simple argument to account for this observation that should be generically valid for a large class of transmembrane and membrane bound proteins. Whenever the protein-lipid interactions locally deform the membrane, that deformation generates new hydrodynamic stresses on the protein-membrane complex leading to a suppression of its mobility. We show that this suppression depends on the protein size in a manner consistent with the work of Y. Gambin et al.