The pulling was carried out as follows: for systems 1-3 slowly over 100 ns, using a pull rate of 0.000033 nm/ps and a spring constant of 10000 kJ/mol/nm 2 . For system 4, the original work did not provide details on the generation of initial windows for the US, so we performed the pulling over 1 ns, using a pull rate of 0.005 nm/ps and a spring constant of 1000 kJ/mol/nm 2 . For system 5, we used the values as in the original work, namely a much faster pulling over 500 ps with a pull rate of 0.01 nm/ps and a spring constant of 1000 kJ/mol/nm 2 .