On 3/7/22 7:56 AM, Altair Hernández wrote: > I would like to use IMP to restrict some proteins to be close to a > membrane (but not in the membrane).

Usually we do this by defining the membrane as a fixed object and restraining the particles relative to it. For example the membrane restraint you found assumes an infinite membrane in the xy plane, and simply restrains particles by their z coordinates. Another example would be a pore where the membrane is represented by a torus and particles are restrained based on their distance to its surface. See the IMP.npc module for those restraints (although those are for PMI1; they would need some minor modifications to work with modern PMI).

> I was checking out the > IMP.pmi.MembraneRestraint class, but no clue about its usage.

Normally you would not use the C++ class directly, but the Python wrapper, in IMP.pmi.basic.restraints. That's fairly well documented: https://integrativemodeling.org/2.16.0/doc/ref/restraints_2basic_8py_source....

> Is there any example I can follow?

https://integrativemodeling.org/2.16.0/doc/ref/pmi_2membrane_8py-example.htm...

> Is IMP creating a membrane instance (displayable in RMF files) or is it > only a restraint instance?

It's just a restraint, although there is a method that creates an MRC file for visualization purposes.

Ben