  The computational study of the interaction between charged, ligand-protected
metal nanoparticles and model lipid membranes has been recently addressed both
at atomistic and coarse grained level. Here we compare the performance of three
versions of the coarse grained Martini force field at describing the
nanoparticle-membrane interaction. The three coarse-grained models differ in
terms of treatment of long-range electrostatic interactions and water
polarizability. The NP-membrane interaction consists in the transition from a
metastable NP- membrane complex, in which the NP is only partially embedded in
the membrane, to a configuration in which the NP is anchored to both membrane
leaflets. All the three coarse grained models provide a description of the
metastable NP-membrane complex that is consistent with that obtained using an
atomistic force field. As for the anchoring transition, the polarizable- water
Martini correctly describes the molecular mechanisms and the energetics of the
transition. The standard version of the Martini model, instead, underestimates
the free energy barriers for anchoring and does not completely capture the
membrane deformations involved in the transition process.
