Fig. 4
From: Into the Dynamics of a Supramolecular Polymer at Submolecular Resolution
Monomer exchange in water-soluble fibre (1) modelled via WT-MetaD simulations. a Free-energy profile of monomer exchange with water as a function of the minimum distance between the activated core and the other cores in fibre (1). Starting from a configuration where the activated monomer (green in the snapshots) is stacked onto a hot spot (red) on the fibre surface (A), the monomer does not diffuse directly in water C, but tends to diffuse onto the surface of fibre (1) (Step 1: A to B) before jumping in the solvent (Step 2: B to C). b Quantitative FES for Step 1 as a function of the minimum core-core distance. c Quantitative FES for Step 2 as a function the distance between the activated monomer and the fibre surface. Error bars in the FESs represent s.e.m. d CG-WT-MetaD snapshots representing the A–B and B–C transitions and the relative timescales (t 1 and t 2) (water not shown for clarity). The spontaneous incorporation of a dissolved monomer into fibre (1) follows the reverse stepwise process (unbiased CG-MD): the monomer (t 3) collapses onto fibre (1) (Step 3) and diffuses on the surface, moving from one hot spot to another (Step 4) with residence time of t 4 (equal to t 1 from WT-MetaD). Exchanging a monomer from the fibre interior (Steps 0–2) is way more infrequent than exchanging monomers present on the fibre surface (see Supplementary Fig. 5a for all computed timescales)
