Fig. 5. Three types of proton potential energy surfaces in biological SHBs. (a) A double-well potential, calculated from the Arg331–Glu328 hydrogen bond in a glucose isomerase (PDB ID 4A8I). (b) A single-well potential with a shoulder, calculated from the Asp35–Tyr109 hydrogen bond in a cellobiohydrolase (PDB ID ; 2V3I). (c) A single-well potential, calculated from the Arg947–Glu972 hydrogen bond in a mineralocorticoid receptor (PDB ID ; 4PF3).72νeq and ΔEν=0 are highlighted for each system.
