msesMD simulation. As for sLe a , the 245 ns msesMD simulations of sLe x in solution display greater similarity to the triplicate 10 s rather than 1 s unbiased MD simulations, with extensive sampling of the F 1-3 and G 1-3,5 regions (Figure ). Significantly, F 4 and G 4 minima are also identified by msesMD. Interestingly the F 4 and G 4 torsional values from msesMD agree well with those of the RSL-bound sLe x X-ray conformer. For the latter,  values of (-70°,150°) and (-70°,-120°) are determined for the Fuc13)GlcNAc and Gal14)GlcNAc linkages respectively. By clustering the msesMD trajectories, a structure closely matching the RSLbound conformer was identified (Figure ). It should be noted that whilst this lectin-like conformer was identified within the top 10 most occupied clusters upon reweighting, the cluster was low in population, with an estimated relative free energy of 5.5 kcal mol -1 above the closed state. This rare conformation could have been overlooked if fewer clusters had been examined and thus highlights the importance of considering relatively low occupation conformations in identifying important glycan shapes.