  We report here on the pitfalls of the simulation model introduced in the
"Capturing Phase Behavior of Ternary Lipid Mixtures with a Refined Martini
Coarse-Grained Force Field" [Journal of Chemical Theory and Computation 2018,
14, 11, 6050-6062]. This refined Martini model was reported to reproduce
experimental phase diagrams for a ternary DOPC/DPPC/cholesterol mixture,
including the coexistence of two liquid phases. However, we demonstrate that
this coexistence only emerged due to an unfortunate choice of simulation
parameters, which leads to poor energy conservation. Specifically, the
constraints on the cholesterol model drained energy out from the membrane,
resulting in two coexisting phases at drastically different temperatures. Using
the simulation parameters recommended for the used cholesterol model, this
artefact is eliminated, yet so is phase coexistence, i.e. experimental phase
diagrams are no longer reproduced. It is important to highlight that the
present comment was submitted to Chemical Theory and Computation. However, it
was rejected without peer-review by the Editor-in-Chief, who stated that the
journal "rarely publishes such material".
