The Effect of Ions on Membrane Elasticity - From Curvature Generation to Vesicle Fusion

Ions and charged peptides can have dramatic effects on the properties of membranes. A case in point is Calcium and its crucial role in vesicle fusion.[1] We simulated Calcium-mediated vesicle fusion using All-atom molecular dynamics[2] and described the effect of Calcium on membrane curvature.[3] With the help of a new approach to determining membrane elastic properties[4] we gained new insights into the mechanism of membrane fusion and curvature generation by ions. Another example of prominent membrane deformations caused by ions is the internalization of arginine rich cell penetrating peptides. We present an investigation of the role of ion pairing[5] and a new mechanism for entry driven by curvature elasticity.[1] Furthermore, we apply our methodology to a host of other ions and membrane compositions in order to explore the molecular origins of curvature generation and membrane stiffening by charged adsorbates.

[1] E. Neher, R. Schneggenburger, Nature 406, 889–893 2000

[2] C. Allolio, A. Magarkar, P. Jurkiewicz, K. Baxova, R. Šachl, M. Hof, D. Horinek,
V. Heinz, R. Rachel, C. Ziegler, P. Jungwirth, submitted 2017

[3] A. Magarkar, P. Jurkiewicz, C. Allolio, M. Hof and P. Jungwirth, J. Phys. Chem. Lett., 8, 518-523 2017

[4] C. Allolio, A. Haluts, D. Harries, in preparation

[5] C. Allolio, K. Baxova, M. Vazdar, P. Jungwirth J. Phys. Chem B., 120, 143-153 2016