Figures and show the free energy landscape (-k B T ln P , where P denotes probability) of BPTI after one 500 ns run of GaMD and WE, respectively. The lowest energy state was set to be zero for each of the free energy landscapes. In particular, the GaMD run with the upper bound of the dual boost potential yielded the maximum number of initial structures on average as compared to the other five GaMD potential settings (see Supplementary Information). Maclaurin expansion to the tenth order was used for GaMD reweighting since using cumulant expansion to the second order is limited for small proteins with 40 residues or less. Figure shows a free energy landscape similar to the one obtained from accelerated molecular dynamics (aMD), which was also obtained using a dual boost potential and Maclaurin expansion to the tenth order for reweighting. Slight differences between the two free energy landscapes may be from using different force field parameters: aMD used the modified Amber ff99SB-ILDN force field, which removed modifications to leucine, aspartic acid, and asparagine to mimic the Anton simulation of BPTI, and GaMD used the Amber ff14SB force field. Metastable states of interest, including the major state M and two minor or excited states m C14 and m C38 , 99 are marked in Figure . M region was defined to be -120