Compound 2 is a smaller analogue obtained by truncation of the aryl-sulfonamide moiety of 1 (Figure ). 2 is reported in literature as a very weak inhibitor (IC 50 ca. 350 µM) . The initial results (Figure ) did not show a decrease in active conformation probability, but rather a broad upshifted distribution. Inspection of the MD trajectories used to build the MSM showed that 2 was only weakly bound and had a tendency to escape its binding site on a timescale of several nanoseconds, casting doubts on the reliability of the results obtained by the protocol. A second MSM was built, this time restraining intermolecular distance between 2 and N193 and E276 with weak flat-bottom biasing potentials (See Figure and methods). These distance restraints were selected to enforce 2 to adopt a binding pose consistent with that observed with 1 throughout the MD simulations. The resulting active state probability distribution (Figure , "2r") was very similar to the reference system, suggesting a lack of functional effect. Extending simulation time or number of simulations reduces model error, but does not suggest inhibitory effect for compound 2r (Supplementary Figure ).