  The determination of potentials of mean force for solute insertion in a
membrane by means of all-atom molecular dynamics simulations is often hampered
by sampling issues. A multiscale approach to conformational sampling was
recently proposed by Bereau and Kremer (2016). It aims at accelerating the
sampling of the atomistic conformational space by means of a systematic
backmapping of coarse-grained snapshots. In this work, we first analyze the
efficiency of this method by comparing its predictions for propanol insertion
into a 1,2-Dimyristoyl-sn-glycero-3-phosphocholine membrane (DMPC) against
reference atomistic simulations. The method is found to provide accurate
results with a gain of one order of magnitude in computational time. We then
investigate the role of the coarse-grained representation in affecting the
reliability of the method in the case of a
1,2-Dioleoyl-sn-glycero-3-phosphocholine membrane (DOPC). We find that the
accuracy of the results is tightly connected to the presence a good
configurational overlap between the coarse-grained and atomistic models---a
general requirement when developing multiscale simulation methods.

Chemical Physics;Soft Condensed Matter