The potential of mean force (PMF) and its RMSD of the association and permeation of vitamin B₁₂ through BtuB upon coupling of the GF-SA method with umbrella sampling (US).

<p>Every 0.2 ns, the RMSD of the PMF was computed taking into account accumulative data. The colors in the legend number each GF-SA-US simulation cycle after which the shown PMFs were computed. This means that the PMFs were calculated based on the data collected from 0 to 1^<i>st</i> cycle, from 0 to 2^<i>nd</i> cycle, etc., and from 0 to 10^th cycle.</p> <p>(TIF)</p>