Membrane fluctuations around inclusions

TL;DR

This paper investigates how membrane fluctuations influence the free energy of protein insertion, revealing that fluctuations reduce effective surface tension and affect pore formation, challenging classical nucleation theory.

Contribution

It introduces a combined numerical and analytical approach to quantify how thermal fluctuations impact membrane inclusion energetics and pore formation.

Findings

Fluctuations decrease effective surface tension.

Finite surface tension is necessary for pore opening.

Results challenge classical nucleation theory.

Abstract

The free energy of inserting a protein into a membrane is determined by considering the variation in the spectrum of thermal fluctuations in response to the presence of a rigid inclusion. Both numerically and through a simple analytical approximation, we find that the primary effect of fluctuations is to reduce the effective surface tension, hampering the insertion at low surface tension. Our results, which should also be relevant for membrane pores, suggest (in contrast to classical nucleation theory) that a finite surface tension is necessary to facilitate the opening of a pore.