Simulation of polyethylene glycol and calcium-mediated membrane fusion.
We report on the mechanism of membrane fusion mediated by polyethylene glycol (PEG) and Ca(2+) by means of a coarse-grained molecular dynamics simulation approach. Our data provide a detailed view on the role of cations and polymer in modulating the interaction between negatively charged apposed membranes. The PEG chains cause a reduction of the inter-lamellar distance and cause an increase in concentration of divalent cations. When thermally driven fluctuations bring the membranes at close contact, a switch from cis to trans Ca(2+)-lipid complexes stabilizes a focal contact acting as a nucleation site for further expansion of the adhesion region. Flipping of lipid tails induces subsequent stalk formation. Together, our results provide a molecular explanation for the synergistic effect of Ca(2+) and PEG on membrane fusion.
Department of Computational Biology, Universität Erlangen-Nürnberg, Staudtstr.5-91058, Erlangen, Germany.
Martina
M
Pannuzzo
Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
Djurre H
DH
De Jong
Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6-95125, Catania, Italy.
Antonio
A
Raudino
Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
Siewert J
SJ
Marrink
D002118:Calcium / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D011092:Polyethylene Glycols / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D008051:Lipid Bilayers; D014867:Water; D011092:Polyethylene Glycols; D002118:Calcium