Hello everybody,

I have to run a Mesocite calculation using the the implicit water version of the Martini forcefield. The authors (J. Chem. Theory. Comput, 2015, 11, 260-275) simulated a lipid bilayer fixing the cell in the direction normal to the bilayer by setting the compressibility to o bar-1. Furthermore, they made the membrane tensionless by setting the reference pressure in the plane of the bilayer to 0 bar. And they assigned a value of 3e-4 bar-1 for the compressibility along the axis of the bilayer plane with a time constant of 4 ps.

They also suggested that implicit-solcent simulations should be run in the NVT ensemble.

I ran an NVT simulation but as the cell dimensión did not change, I couldn´t get the right area per lipid (I calculate this value by dividing the area of my simulation box (Box-X times Box-Y) by half the number of lipids in my system).

Does anybody know how I can treat this issue? Can I fix the Z direction of the simulation box using the NPT ensemble?

Thank you very much.