We then optimized the CG model of the three-branched BTT 58 motif, again using both execution modes. The main results are reported in Figure . Geometrical features of the optimized models are compared to both those calculated from AA-mapped data and from the literature CG model 58 (cf. section 6.2). Using execution mode 1, the BI again yielded an appropriate set of BP at the very first step of the optimization process, with essentially a single group of dihedrals for which distributions were not perfectly adjusted (Figure ). These were fixed during optimization (BP scores down from 31.7 to 20.8) and allowed to retrieve a correct planar geometry of the core of BTT, along with slightly better adjusted geoms distributions (Figure ). Notably, the average and spread of Rg values obtained for the optimized CG model are just slightly larger respect to those of the AA-mapped reference trajectory (Figure : ΔRg of 0.7 Å). Although the error is substantially negligible, this is consistent with the higher dynamicity of CG models compared to the AA ones (this is more evident in BTT, as this motif allows stronger core-to-arms and arms-to-arms interactions compared to e.g. BTA). BP optimization converged within 282 steps (Table ). We tested the manually parametrized CG model of BTT in a 200 ns simulation. BP score and average Rg error for this model were 87.4 and 10.5% with respect to AA-mapped data. The set of optimized BP obtained using execution mode 1 fixed small mismatches observed in local geometrical features of the manually parametrized model (Figure ), while producing a very similar average and spread of Rg values. Using execution mode 2, as expected the BI initially produced an inaccurate set of BP (Figure and cf. SI section 1.1) which was then tuned during optimization. BP scores decreased from 95.6 to 38.0. Again, the optimized BP produced more "loosely" adjusted distributions overlap for angle groups that used equilibrium values at 180° (Figure , angle groups 3 to 8), providing increased flexibility of the CG molecular model with respect to the model optimized via execution mode 1 and AA-mapped data (i.e. average Rg increased by 1.10 Å or 12 points, reaching 10.3 Å). BP optimization converged within 261 steps.