Martin Michael Mueller – Sem phys-bio (at LPTMS)

Protein-membrane interactions with a twist

Martin Michael Müller (U. de Lorraine)

To understand how a biofilament can interact with a lipid membrane, mesoscopic models are of particular interest. Within a framework of elasticity theory and geometry, two mechanisms have been proposed, which can induce membrane deformations due to a biofilament: the Twister and the Darboux torque mechanism [1]. Whereas the Darboux torque mechanism has been shown to explain membrane deformations by a polymer in several important biological systems, the Twister mechanism has been studied more carefully only recently [2].

In my talk I will discuss how the Twister mechanism together with numerical simulations can explain the membrane translocation of botulinium toxins, which are among the most powerful toxins produced in nature. The initial deformation of the membrane by the toxin is caused by the presence of local torques arising from asymmetric positions of hydrophobic residues. Different torque distributions are observed in the simulations and permit an origin for the mechanism opening the membrane to be proposed.

[1] J. Fierling et al. Soft Matter, 12:5747, 2016.

[2] A. Delort et al. IJMS, 25:2481, 2024.