We also examined the consequences of the new GB cavity radii for simple protein simulations by performing 100 ns of unrestrained MD for each protein, using ff14SB, without any bound ligand, in implicit solvent with the mBondi2 and HG-optimized radii, as well with The proteins are also stable when simulated in OBC2 implicit solvent with the original mBondi2 radii, with RMSDs similar to TIP3P except for HSP90, where we observed excess flexibility in residues 100-124. However, implicit solvent simulations with the HG-optimized radii tended to generate greater flexibility, with RMSD values of about 2-4 Å. PWWP1