All simulations were performed using the Berendsen thermostat 63 with the leapfrog integrator, and with the solute and solvent coupled to individual heat baths. The bonds to hydrogen atoms were constrained using the SHAKE algorithm. Cut-offs of 10 and 99Å were used for the calculation of non-bonded interactions involving the protein and water molecules and the EVB region respectively (effectively no cut-off for the latter), and electrostatic interactions for all atoms falling beyond this cut-off were approximated using the local reaction field approach. The nonbonded pairlist was updated every 30 fs. All simulation analysis was performed using the QCalc module of Q, and all structural analysis was performed using VMD version 1.9.3. For full simulation details, see ref. .